Battery pack, battery pack system and electric tool

Abstract

A battery pack comprises a shell, and at least one battery cell is accommodated in the shell; the charging and discharging port is arranged on the shell, the charging and discharging port is provided with a connecting terminal, and the connecting terminal is used for being connected with the battery cell; external equipment is configured to be connected to the battery cell through the charging and discharging port and configured to charge the battery cell or obtain electric energy from the battery cell; the battery pack discharges at a continuous discharge rate greater than or equal to 4C at normal temperature, and the absolute temperature of the battery pack is lower than the charging protection temperature when the discharging is completed.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of and priority to Chinese Patent Application No. CN202210263064.5 filed on March 17, 2022, Chinese Patent Application No. CN202210457481.3 filed on April 28, 2022, and Chinese Patent Application No. CN202211058090.0 filed on August 31, 2022, all of which are incorporated herein by reference in their entirety for all purposes as if fully set forth herein. Technical Field

[0001] The present application relates to the field of power supply systems, and more specifically, to a battery pack, a battery pack system, a power tool, and a power tool system. Related technologies

[0002] Power tools are tools that are actuated by another power source and mechanism, rather than hand tools that are purely used for manual labor. In some cases, such as in outdoor landscaping, power tools need to be used continuously for a long time. Power tools usually use fuel (such as gasoline) and internal combustion engines (hereinafter referred to as fuel-powered tools), and these tools can continue to work for a period of time. For this reason, fuel is often used as a power source for commercial garden tools.

[0003] Commercial garden tools are professional power tools designed for gardeners or garden companies, and are usually equipment used for garden and landscape maintenance. Commercial garden tools usually work on lawns, hedges, flowers, trees or gardens. For example, commercial garden tools can include lawn mowers, lawn mowers, pruners, chain saws, blowers, leaf trimmers and snow blowers.

[0004] Commercial garden tools usually have relatively high power. For example, the power of a garden blower is usually 2300W, and the power of a lawn mower is usually 2600W. Therefore, fuel as a power source can meet the power requirements of commercial garden tools and support the long-term operation of commercial garden tools.

[0005] However, fuel-powered tools are noisy and release exhaust gases that pollute the environment. Power tools use electricity and electric motors or actuators instead of fuel and internal combustion engines. Power tools are environmentally friendly and clean, and they produce less noise than fuel-powered tools. As a result, power tools are becoming more and more popular, even in the context of gardening tools for non-commercial applications. However, the main problem with power tools is that the battery pack has a low output power and a slow charging speed, resulting in a relatively long waiting time for the energy of the power tool, which affects the working efficiency of the power tool. summary

[0006] Some embodiments of the present application provide a battery pack, a battery pack system, a power tool, a power tool system and a method.

[0007] This article describes a battery pack configured to power an electric tool, characterized in that: the battery pack includes a shell, the shell is configured to be connectable to the electric tool; at least one battery cell is located in the shell, the charging rate of each of the at least one battery cell is greater than 5C, each of the at least one battery cell has a capacity of at least 3.6Ah, and the internal resistance of each of the at least one battery cell is less than or equal to 3 milliohms.

[0008] This article also describes a battery pack system, comprising: multiple battery packs, each battery pack comprising: a shell, the shell is configured to be connected to the power tool; and at least one battery cell located in the shell, the charging rate of each of the at least one battery cell is greater than 5C, each of the at least one battery cell has a capacity of at least 3.6Ah, and the internal resistance of each of the at least one battery cell is less than or equal to 3 milliohms.

[0009] The present invention also describes an electric tool comprising: a tool actuator; and a battery pack configured to provide power to the tool actuator, the battery pack comprising: a shell configured to be connectable to the electric tool; and at least one battery cell located within the shell, each of the at least one battery cell having a charge rate greater than 5C, each of the at least one battery cell having a capacity of at least 3.6Ah, and each of the at least one battery cell having an internal resistance less than or equal to 3 milliohms.

[0010] The present invention also describes a battery pack configured to power a power tool, the battery pack comprising: a shell configured to be connected to the power tool; and at least one battery cell located in the shell, the charge rate of each of the at least one battery cell being greater than 5C, and the energy density of each of the at least one battery cell being greater than 120Wh / kg, and wherein the voltage output from each of the at least one battery cell changes approximately linearly during discharge of the battery cell.

[0011] The present invention also describes a power supply system, comprising a first battery pack, a second battery pack, an electric garden tool configured to be powered by the first battery pack and the second battery pack, and a mobile charging device configured to alternately charge the battery packs so that energy is continuously supplied to the electric garden tool, wherein the mobile charging device comprises at least one charging port for receiving the first battery pack and the second battery pack, wherein the mobile charging device is configured to provide energy sufficient for multiple operations, wherein at least one charging port of the mobile charging device has a maximum output power greater than or equal to 3 kW, and charges the first battery pack and the second battery pack at a charging rate of 5C.

[0012] The present invention also describes a power supply system, including a battery pack, an electric garden tool powered by the battery pack, and a mobile charging device including at least one charging port for charging the battery pack, wherein at least one charging port has a maximum output power greater than 3000 W and charges the battery pack at a charging rate of 5C.

[0013] The present invention also describes a power tool system including a power tool and a battery pack, wherein the battery pack includes a housing connectable to the power tool and a battery cell located in the housing, wherein a charging rate of the battery cell is faster than a discharging rate of the battery cell.

[0014] Also described herein is a power tool comprising a battery pack including a housing connectable to the power tool and at least one battery cell within the housing, wherein a charge rate of the battery cell is faster than a discharge rate of the battery cell.

[0015] The present invention also describes an electric tool system comprising a plurality of battery packs and a plurality of electric tools, wherein each of the plurality of battery packs comprises a housing configured to be connectable to an electric tool among the plurality of electric tools and a battery cell located within the housing, wherein the difference between a rate at which the battery cell can be charged and a rate at which the battery cell can be discharged is less than 2C, and wherein a maximum available discharge current of the battery cell is at least 40A.

[0016] Also described herein is a method of operating a battery pack system that includes charging a battery pack, wherein the battery pack is charged at a charge rate not exceeding 5C and discharged at a discharge rate less than 5C.

[0017] Also described herein is a power tool comprising a battery pack including a housing connectable to the power tool and a cell within the housing, wherein the cell charge rate is faster than the cell discharge rate. In some embodiments, the battery pack includes a cell within the housing, wherein the difference between the rate at which the cell can be charged and the rate at which the cell can be discharged is less than 2C, the discharge rate is greater than 6C and the charge rate is greater than 6C, and the cell has a maximum available discharge current of at least 40A.

[0018] The present invention also describes a method for operating a battery pack system. In one embodiment, for multiple workers at a work site, when a worker is using a first battery pack, a second battery pack can be replaced at the work site. When multiple workers move to a second work site, the workers can use the second battery pack to power the garden power tools used by the corresponding workers at the second work site, and charge the first battery pack at the second work site.

[0019] In one embodiment, the method includes: arriving at a first work site, using a first battery pack to power a power tool used at the first work site, wherein the first battery pack is fully charged, charging a second battery pack at the first work site, completing work at the first work site and traveling to the second work site, placing the second battery pack in the power tool at the second work site and using the power tool at the second work site; and, while at the second work site, charging the first battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above-mentioned objectives, technical solutions and beneficial effects of the present invention can be clearly obtained through the detailed description of the following specific embodiments, which can be combined with the description of the accompanying drawings to implement the present invention.

[0021] Figure 1 This is a graph showing how the temperature and voltage of the battery pack change with charge and discharge time when the battery pack according to an embodiment of the present application undergoes a single charge and discharge cycle at a charge rate of 3C and a discharge rate of 10C.

[0022] Figure 2A Illustration of a scenario where a commercial landscaping team uses a vehicle-borne power tool system while on the job.

[0023] Figure 2B Schematic diagram of a commercial garden crew moving between gardens.

[0024] Figure 3A A schematic diagram of a scenario in which a battery pack provided in an embodiment of the present application is used to power a wheeled power tool.

[0025] Figure 3B A schematic diagram of a scenario in which a battery pack provided in an embodiment of the present application is used to power a handheld power tool.

[0026] Figure 4A A schematic diagram of a scenario in which a battery pack on a backpack provided in an embodiment of the present application is used to power a handheld power tool.

[0027] Figure 4B A schematic diagram of a scenario in which a battery pack on a backpack provided in an embodiment of the present application is used to power a handheld power tool.

[0028] Figure 5A This is a schematic diagram of the structure of the battery pack after disassembly according to an embodiment of the present application.

[0029] Figure 5B A schematic diagram of the partial structure of an energy storage unit in a battery pack provided in an embodiment of the present application.

[0030] Figure 5C This is a schematic diagram of the structure of the replacement battery pack provided in an embodiment of the present application when it is disassembled.

[0031] Figure 5D A schematic diagram of the partial structure of an energy storage unit in a replacement battery pack provided in an embodiment of the present application.

[0032] Figure 5E A schematic diagram of the partial structure of an energy storage unit in a battery pack provided in an embodiment of the present application.

[0033] Fig. 5F A cross-sectional view of an energy storage unit in a battery pack according to an embodiment of the present application.

[0034] Figure 6 The embodiment of the present application provides a graph of how the temperature and voltage of the battery pack change with the charge and discharge time when the battery pack is subjected to a single charge and discharge cycle at a charge rate of 3C and a discharge rate of 4C without starting the cooling fan of the charging device.

[0035] Figure 7 The figure is a graph showing how the temperature and voltage of the battery pack change with charge and discharge time when the charging device starts the cooling fan when the battery pack performs a single charge and discharge cycle at a charge rate of 3C and a discharge rate of 3C.

[0036] Figure 8 The embodiment of the present application provides a graph showing how the temperature and voltage of the battery pack change with charge and discharge time when the battery pack performs continuous charge and discharge cycles at a charge rate of 3C and a discharge rate of 4C when the charging device does not start the cooling fan.

[0037] Fig. 9 The embodiment of the present application provides a chart showing how the temperature and voltage of the battery pack change with the charge and discharge time when the charging device starts the cooling fan and the battery pack is continuously charged and discharged at a charge rate of 3C and a discharge rate of 3C.

[0038] Fig.10 The embodiment of the present application provides a graph of how the temperature and voltage of the battery pack change with the charge and discharge time when the charging device starts the cooling fan and the battery pack is continuously charged and discharged at a charge rate of 4C and a discharge rate of 4C.

[0039] Fig.11 A graph of how the temperature and voltage of the battery pack change with charge and discharge time when the charging device starts the cooling fan and the battery pack performs continuous charge and discharge cycles at a charge rate of 6C and a discharge rate of 4C is provided for an embodiment of the present application.

[0040] Fig.12 A chart comparing the OCV curves of the battery pack provided in the embodiment of the present application with the 18650 battery pack.

[0041] Fig.13A chart comparing the OCV curves of the battery pack provided in the embodiment of the present application with the 18650 battery pack.

[0042] Fig.14 A chart comparing the OCV curves of the battery pack provided in the embodiment of the present application with the 18650 battery pack.

[0043] Fig.15 FIG. 4 is a graph showing voltage drop over time according to an embodiment of the present application.

[0044] Fig.16 A schematic diagram of an electric tool system provided in an embodiment of the present application.

[0045] Fig.17 This is a schematic diagram of a power tool system according to another embodiment of the present application.

[0046] Fig.18 This is a schematic diagram of a power tool system according to another embodiment of the present application.

[0047] Fig.19A This is a structural exploded diagram of the battery pack provided in an embodiment of the present application.

[0048] Fig.19B A schematic diagram of the internal structure of a battery pack provided in an embodiment of the present application.

[0049] Fig.19C A schematic diagram of the internal structure of a battery pack provided in an embodiment of the present application.

[0050] Fig.19D A schematic diagram of the internal structure of a battery pack provided in an embodiment of the present application.

[0051] Fig. 20 This is a block diagram of a power tool power system according to another embodiment of the present application.

[0052] Fig.21 A graph showing changes in temperature of a 4Ah battery pack over charging time when the battery pack performs a single charging cycle at a charging rate of 3C is provided for an embodiment of the present application.

[0053] Fig. 22 A graph showing changes in temperature of an 11Ah battery pack over charging time when the battery pack performs a single charging cycle at a charging rate of 3C is provided for an embodiment of the present application.

[0054] Fig.23 A graph showing changes in temperature of a 4Ah battery pack over charging time when the battery pack performs a single charging cycle at a charging rate of 5C is provided for an embodiment of the present application.

[0055] Fig.24A graph showing the temperature of an 11Ah battery pack versus charging time when the battery pack performs a single charging cycle at a charging rate of 5C according to an embodiment of the present application.

[0056] Fig.25 A graph showing changes in temperature of a 4Ah battery pack versus charging time when the battery pack performs a single charging cycle at a charging rate of 10C is provided for an embodiment of the present application.

[0057] Fig.26 A graph showing the temperature of a 11Ah battery pack versus charging time when the battery pack performs a single charging cycle at a charging rate of 10C according to an embodiment of the present application.

[0058] Fig. 27 A graph showing the temperature of a 4Ah battery pack versus discharge time when the battery pack performs a single discharge cycle at a discharge rate of 5C according to an embodiment of the present application.

[0059] Fig.28 A graph showing the temperature of an 11Ah battery pack versus discharge time when the battery pack performs a single discharge cycle at a discharge rate of 5C according to an embodiment of the present application.

[0060] Fig.29 A graph showing the temperature of a 4Ah battery pack versus discharge time when the battery pack performs a single discharge cycle at a discharge rate of 10C is provided for an embodiment of the present application.

[0061] Fig.30 A graph showing the temperature of an 11Ah battery pack versus discharge time when the battery pack performs a single discharge cycle at a discharge rate of 10C is provided for an embodiment of the present application.

[0062] Fig.31 A graph showing changes in temperature of a 4Ah battery pack over charge and discharge time when the battery pack performs a charge and discharge cycle at a charge rate of 3C and a discharge rate of 10C is provided for an embodiment of the present application.

[0063] Fig.32 A graph showing changes in temperature of an 11Ah battery pack over charge and discharge time when the battery pack performs a charge and discharge cycle at a charge rate of 3C and a discharge rate of 10C is provided for an embodiment of the present application.

[0064] Fig.33 A graph showing how the charge rate of a 4Ah battery pack varies with SOC when the battery pack performs a single charge cycle at a charge rate of 5C according to an embodiment of the present application.

[0065] Fig.34 A graph showing how the charge rate of an 11Ah battery pack varies with SOC when the battery pack performs a single charge cycle at a 5.5C charge rate is provided for an embodiment of the present application.

[0066] Fig.35 A circuit block diagram of a mobile charging device provided in an embodiment of the present application.

[0067] Fig.36 A schematic diagram of the installation of a vehicle-mounted mobile charging device provided in an embodiment of the present application.

[0068] Fig.37 A circuit block diagram of how a mobile charging device provided in an embodiment of the present application switches between a first charging mode and a second charging mode.

[0069] Fig.38 Schematic diagram of a 4Ah battery cell according to an embodiment of the present application.

[0070] Fig.39 Schematic diagram of an 11Ah battery cell according to an embodiment of the present application.

[0071] Fig.40 Schematic diagram of a scenario where a commercial landscaping crew uses a power tool system for an out-of-town job.

[0072] The same reference numerals and symbols are used in the drawings and the description to designate the same or equivalent elements. DETAILED DESCRIPTION

[0073] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more explicit definition of the protection scope of the present invention. The following embodiments can be appropriately combined with each other. The same reference numerals and symbols in different embodiments in the drawings and the specification are used to represent the same or equivalent elements.

[0074] As mentioned above, different types of power tools can be powered by either fuel or electricity. Fuel-powered tools can provide high power and can work continuously for long periods of time. Therefore, fuel-powered tools are often used in commercial gardening.

[0075] However, as mentioned above, fuel-powered tools cause environmental pollution and are noisy.

[0076] Electricity is an environmentally friendly and clean energy source, and electricity can be generated by renewable energy. Therefore, electric tools powered by electricity are becoming more and more popular. Usually, electric tools are powered by a DC power supply or an AC power supply. The DC power supply can be a portable power supply such as a battery pack or an energy storage cabinet, and the AC power supply can be the mains power, which can be obtained through an AC socket.

[0077] Commercial garden tools are often provided by garden companies. Since they need to be connected to an outlet, it is difficult to obtain AC power when the garden company is out working. Therefore, in the field of commercial garden tools, DC power may be more preferred. In this way, the battery pack can be used to power the power tool, and it is easier for the work team to carry the battery pack during the outing.

[0078] Gardening companies usually have two to three people forming a work team and work outdoors for one or more days. When going out to the work site, the gardening team uses vehicles to carry various fuel tools, such as fuel mowers, fuel blowers, fuel pruning machines, and fuel lawn mowers required for the work. Fuel tools can be quickly replenished from gasoline tanks. Therefore, after completing the work in one garden, the gardening team uses vehicles to carry various fuel tools and transfer the tools to the next garden to continue working.

[0079] According to the embodiments disclosed herein, a new type of battery cell, referred to herein as a Type 2 battery cell, is used in power tools. This Type 2 battery cell can be charged and discharged quickly enough to make similar working scenarios possible. Specifically, Figure 2A and Figure 2B As shown, the work team uses a vehicle to carry various garden power tools required for the work, such as wheeled power tools such as a push mower 201, an intelligent mower 202, and handheld power tools such as a mower 301, a pruning machine 302, and a hair dryer 303. The work team also needs to carry a DC power supply, such as a battery pack and a charging device. The charging device can charge the battery pack. During the work process, the work team first comes to the first garden and uses various garden power tools carried to work. For garden pruning work, mowing usually takes the longest time. Although the size of lawns in different households is different, the average time consumed for mowing is between 20 minutes and 40 minutes. Therefore, every time a worker arrives at the garden, he will immediately start mowing with a mower. During the mowing process, another worker completes other types of work in sequence by using a handheld power tool. For example, another worker first mows, trims, and then blows the grass. The two workers complete all the work almost at the same time, and then the work team moves to the second garden. Repeatedly, until the day's work is completed. In some other embodiments, a top handle saw or a chain saw can also be used as part of the power tool.

[0080] In some cases, the battery pack provided herein includes at least one battery cell, and may include multiple battery cells. The battery cell may have any suitable shape assembled in the housing, preferably a cuboid shape (e.g., a sheet-like rectangular shape). Each battery cell may have an energy of not less than 16Wh. Depending on the size and / or weight requirements of the battery pack, the battery pack may include from 1 battery cell to 100 battery cells. For example, the battery pack may include 5 battery cells, 10 battery cells, 15 battery cells, 20 battery cells, 25 battery cells, 50 battery cells, 75 battery cells, or 100 battery cells. In some preferred embodiments, the battery pack includes 15 battery cells. In some aspects, the internal resistance of all multiple battery cells in the battery pack is less than 30 milliohms, and the multiple battery cells have a capacity of at least 4Ah. In one embodiment, the battery pack includes multiple battery cells, and the internal resistance of all battery cells in the battery pack is less than 30 milliohms, and the multiple battery cells have a capacity of at least 11Ah.

[0081] In some cases, the cell charge rate is faster than the discharge rate. For example, a cell may be charged at a rate of 10C and discharged at a rate of 4C.

[0082] As an example, Figure 2A As shown, the charging device may be a mobile charging device 400. The energy storage capacity of the mobile charging device 400 is much greater than the energy storage capacity of the battery pack. The gardening team can fully charge the mobile charging device 400 at night and carry the mobile charging device 400 when going out to work during the day, so that the mobile charging device 400 is always powered during working hours and replenishes power for the power tools in time.

[0083] In order for electric tools to have the power of fuel tools, the battery pack needs to meet the power requirements of commercial garden tools. For example, compared to a fuel garden mower, the output power of an electric lawn mower needs to reach 1200W or more. Compared to a fuel blower, the output power of an electric hair dryer needs to reach 1500W to 3000W. Compared to a fuel mower, the power of an electric lawn mower needs to reach 2000W to 3000W.

[0084] According to the provided battery pack, during the discharge period, the continuous discharge current of the single cell in the battery pack is not less than 20A. Generally, the voltage platform formed by the single cell in the battery pack is 60V, that is, the nominal voltage of the battery pack is 60V. Therefore, when the discharge current of the single cell is not less than 20A, the output power of the battery pack is not less than 1200W, which can meet the power requirements of commercial electric garden tools.

[0085] Optionally, the continuous discharge current of the single cell in the battery pack is not less than 40 A. When the nominal voltage of the battery pack is 60 V, the output power of the battery pack is not less than 2400 W, which can meet the power requirements of high-power electric tools such as electric lawn mowers and electric hair dryers.

[0086] Optionally, the continuous discharge current of the single cells in the battery pack is not less than 60A, 70A, 80A or 100A.

[0087] In another embodiment, the nominal voltage of the battery pack is not limited to 60V. For example, the nominal voltage of the battery pack may also be 20V, 36V, 48V, 96V, etc. Since the continuous discharge current of the single cell in the battery pack is relatively large, the battery pack can still meet the requirements of high-power power tools even when the nominal voltage of the battery pack is relatively low. For example, when the nominal voltage of the battery pack is 20V, since the continuous discharge current of the single cell is not less than 60A, the output power of the battery pack is not less than 1200W. Therefore, since the discharge current of the single cell is relatively large, the provided battery pack can meet the high power requirements of the power tool. At present, the nominal voltage of the battery pack is generally 60V. Therefore, a battery pack with a voltage platform of 60V is taken as an example for explanation.

[0088] During discharge, the battery pack does not necessarily discharge continuously at a large current. In actual working process, the discharge current of the battery pack can be set according to the requirements of the power tool. For example, when fully charged, the battery pack can be discharged at a large current, and when discharged to a low voltage, the battery pack can be discharged at a small current, or it can be discharged at a constant current value. Since the average output power of most garden power tools is around 1800W, the average discharge current of the battery pack is not less than 30A. Therefore, the average output power of the battery pack is not less than 1800W, which can meet the requirements of most garden tools.

[0089] According to the battery pack provided, the capacity of the battery pack is designed by comprehensively considering the weight, battery life, power and user habits of the battery pack. First, the weight of the battery pack cannot be too heavy, so that the battery pack does not affect the comfort of use when it is installed on the power tool or carried on the user's back. Second, after the battery pack is installed on the high-power garden power tool, the battery life of the battery pack can achieve a low replacement frequency. Third, the battery pack can be installed on the power tool for convenient use, and it is best to conform to the workers' usage habits when using conventional fuel tools. When the garden team uses conventional fuel tools, they will fill up all the fuel tools they carry before going out to work, so that they can be used directly without refueling the tools before each use.

[0090] like Figure 3A-3BAs shown, based on the diversity and convenience of garden tools, the present application discloses and provides two types of battery packs, namely a first type battery pack 101 (first embodiment) and a second type battery pack 102 (second embodiment). The capacity of the first type battery pack 101 may be greater than the capacity of the second type battery pack 102. The first type battery pack 101 is configured to power power tools with large size and high power, such as wheeled or backpack power tools 200, including a push mower 201, a smart mower 202, and a riding mower 203. During use, the first type battery pack 101 can be directly mounted on the wheeled or backpack power tool 200, and the user does not need to directly bear the weight of the battery pack.

[0091] The second type of battery pack 102 is configured to supply power to a handheld power tool 300, such as a lawn mower 301, a pruning machine 302, and a hair dryer 303. The second type of battery pack 102 can be directly installed on the handheld power tool 300, and the staff does not need to supply power to the handheld power tool 300 through a cable when using the handheld power tool 300, which is more convenient to use. When working outside, the garden team can pre-install the second type of battery pack 102 on each handheld power tool 300 carried, so that when switching from one handheld power tool to another handheld power tool, the other handheld power tool can be used directly without installing the battery pack. This makes it more in line with the habits of workers who have been trained to use traditional fuel tools. For example, the handheld power tool 300 of the garden power tool system includes a lawn mower 301, a pruning machine 302, and a hair dryer 303. The garden team can pre-install the second type of battery pack 102 on the lawn mower 301, the pruning machine 302, and the hair dryer 303 before working in the garden each time. After mowing is completed, the worker can use the pruning machine 302 to prune directly without installing a battery pack on the pruning machine 302. After pruning is completed, there is no need to install a battery pack on the hair dryer 303, and the hair dryer 303 can be used directly for blowing.

[0092] When the working area has a relatively large area, the first type battery pack 101 can also be used to power the handheld power tool 300 to extend the working time of the handheld power tool 300 and reduce the frequency of battery pack replacement. Figure 4A As shown, in this embodiment, the battery pack system further includes a backpack device 103. The first type of battery pack 101 is detachably mounted on the backpack device 103. The backpack device 103 further includes a power cord 104. A power port 105 is provided at one end of the power cord 104 (for example, a port for connecting the battery pack to a power tool). The handheld power tool 300 is provided with a tool port that matches the power port 105. The first type of battery pack 101 can be connected to the handheld power tool via the power cord 104 and the power port 105 to supply power to the handheld power tool 300. Figure 4B As shown, the power port 105A can be configured to match the tool port 410 on the commercial power tool. For example, the first type of battery pack 101 is first connected to the lawn mower 301, and the operator uses the lawn mower 301 to mow the lawn. After the lawn mowing is completed, the connection between the lawn mower 301 and the first type of battery pack 101 is released, and then the pruning machine 302 is connected to the first type of battery pack 101, and the pruning machine 302 starts working. After the pruning is completed, the connection between the pruning machine 302 and the first type of battery pack 101 is released, and the hair dryer 303 is connected to the first type of battery pack 101 to start working.

[0093] Figure 5A It is a schematic diagram of the structure of a first type of battery pack 101. The first type of battery pack 101 includes a shell 21, a charge and discharge port 22 and an energy storage unit 23. The charge and discharge port 22 is arranged on the shell 21. A connecting terminal is arranged in the charge and discharge port 22 for connecting the energy storage unit 23. An external device can be connected to the energy storage unit 23 through the charge and discharge port 22, and is configured to charge the energy storage unit 23 or obtain electric energy from the energy storage unit 23. The energy storage unit 23 is arranged in the shell 21. The energy storage unit 23 is composed of a plurality of single cells 231, and each single cell 231 is a sheet battery. The plurality of single cells 231 overlap in the thickness direction H of the single cells, and the plurality of single cells 231 are connected in series. As shown Figure 5B As shown, there is an air gap between adjacent single cells 231 in the stacking direction, and the distance Δh between two adjacent single cells 231 is greater than or equal to 1 / 12 of the thickness H of the single cell 231. Therefore, an air gap is provided between the single cells 231, and the air gap is connected to the outside so that air flow can pass through the air gap to help the battery dissipate heat. In an optional embodiment, the thickness H of the single cell 231 is in the range of 11mm to 14mm. Optionally, the thickness H of the single cell 231 is 12.5mm±0.5mm. The distance Δh between two adjacent single cells 231 is 1.5mm±0.5mm.

[0094] The number of single cells in the first type battery pack 101 is not more than 15. The capacity of the battery pack is not less than 11Ah, and its energy is not less than 600Wh. The first type battery pack 101 has a weight of not more than 8kg (e.g., about 7.8kg), and can be installed on a push mower, an intelligent mower, or a riding mower and configured to power the mower, and can also be installed on a backpack device. The user puts the battery pack on the back to use to power a handheld power tool.

[0095] like Figure 5CAs shown, the structure of the second type battery pack 102 is similar to that of the first type battery pack 101, and further includes a shell 31, a charge and discharge port 32 and an energy storage unit 33. The charge and discharge port 32 is arranged on the shell 31. The energy storage unit 33 is arranged in the shell 31. The energy storage unit 33 is composed of a plurality of single cells 331. Each single cell 331 is a sheet-like structure. A plurality of single cells 331 are stacked in the thickness direction H thereof. The size of the single cell 331 in the second type battery pack 102 is smaller than the size of the single cell 231 in the first type battery pack 101. Accordingly, the capacity of the single cell 331 in the second type battery pack 102 is smaller than the capacity of the single cell 231 in the first type battery pack 101. Similarly, as Figure 5D As shown, in the second type battery pack 102, there is also an air gap between the adjacent single cells 331 in the stacking direction, and the distance Δh between two adjacent single cells 331 is greater than or equal to 1 / 12 of the thickness H of the single cell 331. Therefore, an air gap is provided between the single cells 331, and the air gap is connected to the outside so that air flow can pass through the air gap to help the battery dissipate heat. In an optional embodiment, the thickness H of the single cell 331 is in the range of 8mm to 10mm. Optionally, the thickness H of the single cell 331 is 8.7mm±0.5mm. The distance Δh between two adjacent single cells 331 is 1.5mm±0.5mm.

[0096] The number of single cells 331 in the second type battery pack 102 is not more than 15. The capacity of the battery pack is not less than 4Ah, and the energy is not less than 216Wh. The weight of the second type battery pack 102 is not more than 3.5kg (for example, about 3kg), and can be directly mounted on a handheld power tool 300 such as a lawn mower 301, a pruning machine 302, or a hair dryer 303, and is configured to provide power to the handheld power tool 300.

[0097] like Figure 5E As shown, the battery pack includes an air inlet 510 and an air outlet 520 that allow air cooling during charging. When the battery pack is connected to a charger, a fan in the charger exhausts air for the battery pack through the air outlet 520 of the battery pack. Similarly, as shown in FIG. Fig. 5F As shown, the gaps 540 between cells allow inter-cell cooling. The air ducts 530 act as manifolds to promote airflow between the cells. Finally, the heat sink 550 that contacts the control circuit absorbs heat from the control circuit into the airflow path, also providing cooling for the control circuit.

[0098] Therefore, the design using the battery pack capacity can support the work of high-power power tools. In addition, a second type of battery pack with relatively small capacity is designed for handheld power tools. Workers can configure a battery pack for each power tool. When replacing handheld power tools, there is no need to switch energy sources, which is in line with the usage habits of traditional fuel tools.

[0099] In addition, the continuous discharge rate of the single cells in the first type battery pack 101 is not less than 4C (rate = current / capacity). Since the capacity of the first type battery pack 101 is not less than 11Ah, the continuous discharge current of the first type battery pack 101 is not less than 40A (for example, 44A).

[0100] The continuous discharge rate of the single cells in the second type battery pack 102 is not less than 10 C. Since the capacity of the second type battery pack 102 is not less than 4 Ah, the continuous discharge current of the second type battery pack 102 is not less than 40 A.

[0101] It should be noted that the continuous discharge rate refers to the discharge rate at which the battery pack can be continuously discharged from a fully charged state to an empty state. The continuous discharge rate can identify the discharge capacity of the battery pack.

[0102] According to the provided battery pack, the discharge capacity of the single cell is not limited thereto and can support a higher discharge rate. Specifically, the continuous discharge rate of the single cell in the battery pack is not less than 10C and can reach 10C to 100C. When the discharge rate of the battery pack is within this range, the battery will not be damaged.

[0103] Optionally, the continuous discharge rate of the single cells in the battery pack can reach 10C to 20C. For example, the continuous discharge rate of the battery pack can be 10C, 15C or 20C. When the continuous discharge rate of the single cells in the battery pack is within the range of 10C to 20C, the battery pack can support the operation of a large number of high-power power tools, and within this rate range, the battery pack has a relatively low temperature rise after the discharge is completed, and charging can be started without waiting after the discharge is completed.

[0104] Optionally, the continuous discharge rate of the single cells in the battery pack can reach 20C to 30C. For example, the continuous discharge rate of the battery pack can be 20C, 25C or 30C. When the continuous discharge rate of the single cells in the battery pack is within the range of 20C to 30C, the battery pack can support the operation of higher power electric tools.

[0105] Optionally, the continuous discharge rate of the single cell in the battery pack can reach 30C to 50C. For example, the continuous discharge rate of the battery pack can be 30C, 40C or 50C. When the continuous discharge rate of the single cell in the battery pack is 30C to 50C, in addition to the field of power tools, it can also be further used in other high-power electrical appliances.

[0106] Optionally, the continuous discharge rate of the single cells in the battery pack can reach 50C to 100C. For example, the continuous discharge rate of the battery pack can be 50C, 60C, 70C, 80C, 90C or 100C. When the continuous discharge rate of the single cells in the battery pack is in the range of 50C to 100C, after discharge, the surface temperature of the battery pack (for example, the temperature outside the shell) exceeds the normal operating temperature range of the battery pack, and it is necessary to wait for the battery pack to cool down before charging.

[0107] It can be understood that the continuous discharge rate of the single cells in the battery pack can reach 10C to 100C, which does not mean that the single cells in the battery pack must operate at a discharge rate of 10C or higher, that is, the single cells in the battery pack can also be discharged at a rate less than 10C. The discharge rate of the battery pack can be set specifically according to the power of the power tool.

[0108] In some embodiments, when the battery pack is charged at a 3C rate at ambient temperature (e.g., about 20°C), the battery pack may experience a temperature rise of no more than 15°C (e.g., from about 17°C to about 32°C). Similarly, when the battery pack is charged at a 5C rate at ambient temperature, the battery pack temperature rise does not exceed 17°C, for example, from about 22°C to about 39°C. In addition, when the battery pack is charged at a 10C rate at ambient temperature (e.g., about 25°C), the battery pack temperature rise may not exceed 21°C, and in some cases rises from about 22°C to about 43°C.

[0109] In addition, when the charge rate is 4C and the discharge rate is 4C, the temperature rise of the battery pack during the first cycle of at least six charge and discharge cycles can be less than 20°C. The battery pack can be configured to discharge and charge continuously for at least six charge and discharge cycles without idle time. When cycling without idle time, the temperature rise of the battery pack during the charge and discharge cycle can be from about 15°C to about 25°C at a charge rate of about 6C to about 8C.

[0110] In certain embodiments, such as Figure 1As shown, the battery pack includes a charge rate of 3C and a discharge rate of 10C. When the battery pack is charged at a rate of 3C, the temperature rise of the battery pack can be up to 15°C. In contrast, when the battery pack is discharged at a rate of 10C, the battery pack can exhibit a temperature rise of no more than 35°C. Preferably, after charging the battery pack at a charge rate of 3C, the absolute temperature of the battery pack is lower than a predetermined discharge protection temperature. Similarly, after discharging the battery pack at a discharge rate of 10C, the absolute temperature of the battery pack is lower than the charge protection temperature. When these parameters are met, the battery pack can be discharged immediately after charging, and after discharging, the battery pack can be charged immediately after discharging. The above charge and discharge cycle can be performed at least 2 times. For example, when the cycle is performed twice (e.g., charging at 3C, discharging at 10C, charging at 3C, and discharging at 10C), the absolute temperature of the battery pack is still lower than the discharge protection temperature of about 60°C. Ultimately, the absolute temperature of the battery pack may be higher than the predetermined protection temperature, and the battery pack must be cooled before any further charging or discharging. As used herein, the discharge protection temperature is a temperature that is too high for safe battery pack discharge, and the charge protection temperature is a temperature that is too high for safe battery pack charging. Therefore, the logic circuit in the charging device and / or the power tool will trigger a protection protocol that does not allow the battery pack to charge or discharge, respectively.

[0111] In order to be used as a commercial garden tool, the electric tool needs to complete enough work per unit time and needs to work continuously within a day's working hours. Accordingly, this requires a continuous energy supply for commercial garden power tools. Therefore, when traditional fuel tools are replaced by electric tools, it is also necessary to consider the improvement of the working efficiency of the electric tools, that is, the tools can be used continuously or all day long. In addition to improving working efficiency by using high-power electric tools, according to another aspect, it is also necessary to reduce the energy replenishment time of the electric tools. Therefore, the electric tool does not need to wait for energy, that is, energy is continuously supplied to the electric tool so that the electric tool can work continuously.

[0112] Based on this, there are two ways to provide energy for power tools. The first energy replenishment method is that the work team carries all the energy needed for a day's work outside; the second energy replenishment method is that the work team carries part of the energy and recharges it during the journey. Describe each energy replenishment method in turn.

[0113] For the first energy replenishment method, the following specific energy replenishment plans can be proposed:

[0114] As a first example, you can carry a battery pack that is sufficient to support the energy required for a day's work. The capacity of the battery pack can support multiple power tools to work for a day. In a typical usage scenario, the battery pack first powers a lawn mower, which can be a smart lawn mower, a hand-push lawn mower, etc. After the mowing work is completed, the battery pack continues to power the lawn mower to perform the mowing work. After the mowing work is completed, the battery pack powers the pruning machine to perform the pruning work. After the pruning work is completed, the battery pack powers the hair dryer to complete the blowing work.

[0115] As a second example, each power tool required for gardening work can be configured with a battery pack that is sufficient to support one day's work. For example, if the gardening power tool system includes a lawn mower, a grass trimmer, a pruner and a hair dryer, four battery packs can be carried. The energy of the four battery packs can support the lawn mower, the grass trimmer, the pruner and the hair dryer to work for one day without changing the battery.

[0116] As a third example, a garden power tool system can be configured with multiple battery packs sufficient to support a day's work, some of which are working battery packs and the other part are backup battery packs. For example, the garden power tool system includes a lawn mower, a grass trimmer, a pruner, and a hair dryer. You can configure a working battery pack for each power tool, and then configure a sufficient number of backup battery packs for each power tool. When the power of the working battery pack is used up, the backup battery pack is replaced until the power tool completes all the work. The total capacity of the working battery pack and the backup battery pack is sufficient to support the corresponding power tool to work uninterruptedly outside for a day.

[0117] For the second energy supply method, multiple battery packs can be configured for the power tool system according to different usage scenarios, and the multiple battery packs are charged in turn to power the power tool system. The multiple battery packs are divided into two groups, one group is a working battery pack and the other group is a backup battery pack. When the working battery pack is installed on the power tool and discharged, the backup battery pack is charged. Before the working battery pack is emptied, the backup battery pack is full, and then the backup battery pack is installed on the tool to power the tool, and the working battery pack is charged, and this cycle is repeated to achieve uninterrupted power supply. For example, if the power tool system includes a lawn mower, a grass trimmer, a pruning machine and a hair dryer, and the work team consists of two people (worker A and worker B), where worker A uses a lawn mower to complete the mowing work, and worker B uses a lawn trimmer, a pruning machine and a hair dryer to complete other work, then two groups of battery packs can be configured for worker A's work, one group as a working battery pack and one group as a backup battery pack, and two groups of battery packs can be configured for worker B's work, one group as a working battery pack and one group as a backup battery pack. When the working battery pack runs out of power, the backup battery pack is used to supply power and the working battery pack is charged to achieve uninterrupted power supply by the two battery packs in turn. In this example, four battery packs can be configured for workers A and B, two of which are used as working battery packs and two as backup battery packs. In another example, when the charging speed of the battery pack is slow, six or more battery packs can also be configured for workers A and B, some of which are used to support the work of worker A and the other part is used to support the work of worker B.

[0118] Both of the above energy supply methods can realize uninterrupted operation of the power tool system, but commercial gardening tools are usually equipped by gardening companies. Due to their commercial nature, the cost of use is a factor that must be considered for commercial tools. At the same time, operational convenience is also a factor to consider. If the battery pack is too large and heavy, it will be inconvenient to operate and will also affect work efficiency.

[0119] The requirements of the first energy replenishment method for the battery pack configuration result in the battery pack capacity needing to be large enough, or the number of battery packs being large enough, in order to support the power tool to work non-stop outside for a day. In the prior art, the capacity of common single cells on the market is generally small (generally less than 5Ah). If you want to increase the capacity of the battery pack, it is easy to think of increasing the number of single cells in the battery pack, which will undoubtedly increase the volume and weight of the battery pack. For the energy replenishment methods shown in the first and second examples, the weight and volume of the battery pack are too large, which will cause inconvenience in operation whether it is installed on the power tool or carried on the user's back. In the third example, carrying a large number of battery packs will result in a higher cost of using the power tool, and too many battery packs are inconvenient to carry.

[0120] The second energy supply method configures a limited number of battery packs for the power tool system according to the usage scenarios of commercial garden power tools and the number of staff in the garden team. Multiple battery packs can be alternately charged and discharged to supply power to the power tool system. The usage cost of the power tool system is relatively low, and the small number of battery packs is convenient for carrying.

[0121] Therefore, considering both the usage cost and convenience, it is preferred to use the second energy supply method to power the power tool system. This requires that the charging speed of the battery pack be fast enough so that the spare charging battery pack can be fully charged before or when the battery pack on the power tool is discharged.

[0122] When the battery pack system includes N spare battery packs, the total charging speed of the N spare battery packs should be greater than or equal to the discharging speed of one working battery pack, that is, N * V_charging ≥ V_discharging. N is an integer greater than or equal to 1, V_charging is the charging speed of the battery pack, and V_discharging is the discharging speed of the battery pack. Among them, the charging and discharging speed of the battery pack depends on the charging and discharging rate of the battery pack. Therefore, the above formula can be converted to N * C_charging ≥ C_discharging, where C_charging is the charging rate of the battery pack and C_discharging is the discharging rate of the battery pack. When the number of spare battery packs is 1 (i.e., N = 1), that is, when the power tool includes one working battery pack and one spare battery pack, it is required that the charging speed of the spare battery pack be greater than or equal to the discharging speed of the working battery pack. When the number of spare battery packs is multiple (i.e., N > 1), it is required that the total charging speed of the multiple spare battery packs be greater than the discharging speed of one working battery pack. For example, when N is 2, that is, the charging speed of the two spare battery packs should be greater than or equal to the discharging speed of one working battery pack. The power tool needs to be configured with three battery packs to achieve uninterrupted operation. When the first battery pack is installed on the power tool, after the first battery pack is discharged, the second battery pack is installed on the tool and the first battery pack is charged. After the second battery pack is discharged, the third battery pack is installed on the power tool and the second battery pack is charged. At this time, both the first battery pack and the second battery pack are being charged. Before the third battery pack is discharged, the first battery pack is fully charged. Thus, after the third battery pack is discharged, the first battery pack can be installed on the power tool so that the power tool can operate uninterruptedly. To reduce the usage cost of the battery pack and make it convenient for the garden team to carry out, preferably, the smaller the value of N, the better, that is, the fewer the number of spare battery packs carried. This requires that the charging rate and discharging rate of the battery pack be equivalent. Preferably, the charging rate is greater than or equal to the discharging rate. It can be understood that the working battery pack and the spare battery pack mentioned in this example are battery packs of the same specification. When the battery pack refers to the one installed on the power tool to support the operation of the power tool, this battery pack is the working battery pack, and the rest of the battery packs are spare battery packs.

[0123] In order to improve the working efficiency of the power tool and realize the uninterrupted operation of the power tool, in addition to reducing the charging time of the battery pack, it is also necessary to reduce the waiting time after the battery pack is charged and discharged. The reason is that in the prior art, when the battery pack capacity is constant, the greater the charging and discharging current in the battery pack, the more serious the heat of the battery pack. If the temperature of the battery pack is too high and exceeds the normal operating temperature range of the battery pack, the battery pack will turn on the temperature protection mechanism during the charging and discharging process, after the charging or after the discharging, and stop charging / discharging, and wait for the temperature to drop to a safe temperature before continuing to charge / discharge. Therefore, in order to allow the power tool system to have a continuous energy supply, the battery pack can be immediately installed on the power tool for discharge after charging, and can be charged immediately after discharging without waiting for cooling. This requires that the maximum temperature of the battery pack during the charging and discharging process must not exceed the temperature protection threshold of the battery pack, and the maximum temperature must not exceed the temperature protection threshold after the uninterrupted charging and discharging superposition process ends, so that the battery pack can continue to charge and discharge the next round without waiting after one round of charging and discharging ends.

[0124] The battery packs on the market usually cannot meet the charging rate and temperature rise requirements of commercial garden power tools for battery packs. Taking the common ternary lithium battery system 18650 battery pack as an example, the continuous charging rate of the battery pack is less than 3C, usually 0.5C~1C, and the charging speed is slow. If the charging current is increased and the charging rate is increased, the surface temperature of the battery pack will rise rapidly. If the battery pack starts discharging immediately after charging, the temperature base of the battery pack discharge will be high. As a result, after a charge and discharge cycle, the temperature of the battery pack has reached the temperature protection threshold and the next round of charging and discharging cannot be performed. This means that after a battery pack is fully charged and used once, it needs to be left standing and waited for cooling. The next round of charging and discharging can only be started after the temperature drops to room temperature. Therefore, if you want to achieve uninterrupted operation of power tools, you need to prepare multiple sets of spare battery packs.

[0125] In addition, current battery pack chargers usually use AC power to charge battery packs, that is, one end of the charger is connected to the AC power through a socket, and the other end is connected to the battery pack, converting the AC power into DC power to charge the battery pack. However, due to the safety regulations of the socket, the output power of the socket is limited, and it is impossible to provide a large current to charge the battery pack. For example, the standard voltage of the AC power in the United States is 110V, and the fuse current of most sockets is 15A, so the power that most sockets can withstand does not exceed 1800W. Therefore, the current battery pack charging power is limited by two factors. On the one hand, the AC power cannot provide a large output power to charge the battery pack, and on the other hand, the battery pack itself cannot accept high-power charging.

[0126] The present application provides a battery pack, the charging rate and the temperature rise of the battery pack after charging and discharging can meet the needs of commercial garden power tools, and can improve the working efficiency of commercial garden power tools.

[0127] Specifically, the continuous charging rate of the single cell in the battery pack is not less than 3C, and fast charging can be supported. In this embodiment, the continuous charging rate of the single cell in the battery pack can reach 3C to 20C, that is, the charging rate of the single cell in the battery pack can be 3C, 4C, 5C, 6C, 7C, 8C, 9C, 10C, 11C, 12C, 15C or 20C. It can be understood that the charging capacity of the single cell in the battery pack is greater than or equal to 3C, which does not mean that the single cell can only be continuously charged at a rate greater than or equal to 3C. In some scenarios, the single cell in the battery pack can also be continuously charged at a charging rate less than 3C, such as 1C or 2C.

[0128] As a specific example, during the charging process of the first type battery pack 101 from an empty state to a fully charged state, the continuous charging rate of the single cell is not less than 6C, and during the charging process of the second type battery pack 102 from an empty state to a fully charged state, the continuous charging rate of the single cell is not less than 12C. In the present application, the single cells in the battery pack are connected in series, so the charging rate of the battery pack is equal to the charging rate of the single cell. That is, the continuous charging rate of the first type battery pack 101 is not less than 6C, and the continuous discharge rate is not less than 4C, and the continuous charging rate of the second type battery pack 102 is not less than 12C, and the continuous discharge rate is not less than 10C. It can be understood that the continuous charging rate of the battery pack is used to identify the capacity of the battery pack, and it does not mean that the battery pack must be charged and discharged at this capacity, that is, the battery pack can also be charged and discharged at a charge and discharge rate less than this capacity, which is determined according to actual conditions.

[0129] In addition, the present application also provides a mobile charging device, whose output power is greater than the mains power and can provide a large current to charge the battery pack. Figure 2AAs shown, the mobile charging device 400 can be an energy storage cabinet that stores electric energy by itself. The mobile charging device 400 can be placed on a vehicle and moved to various gardens with the power tool system by the user so as to recharge the exhausted battery pack at any time, avoiding the difficulty of the user in finding a power supply when the user is moving. For example, for each of the multiple workers at the work site, when the worker is using the first battery pack, the second battery pack can be charged at the work site. When the multiple workers move to the second work site, the workers can use the second battery pack to power the gardening power tools used by the corresponding workers at the second work site, and charge the first battery pack at the second work site. For example, the method includes arriving at the first work site, using the first battery pack to power the power tools used at the first work site, wherein the first battery pack is fully charged; charging the second battery pack at the first work site; completing the work at the first work site and then going to the second work site; when at the second work site, placing the second battery pack in the power tool and using the power tool at the second work site; and charging the first battery pack at the second work site.

[0130] The mobile charging device 400 is an energy storage charging device. The user can fully charge the energy storage device in the mobile charging device 400 at night, and use the mobile charging device 400 to recharge the battery pack when working outside during the day. The charging method of the mobile charging device 400 is DC charging, and the output power of the mobile charging device 400 is not less than 2400W. Preferably, the output power of the mobile charging device 400 is not less than 3600W when the charging rate is 5C to support high-current charging. Therefore, the battery pack provided in the present application not only has its own ability to withstand high-rate charging, but also the mobile charging device 400 provided in the present application can provide a large current to charge the battery pack.

[0131] In some cases, the system described herein may include multiple battery packs that can be charged alternately to continuously power various power tools. For example, a first battery pack and a second battery pack may be configured to power an electric garden tool. The mobile charging device may be configured to accept one or two battery packs at any given time. In this example, the mobile charging device may charge the battery packs alternately so that electrical energy is continuously supplied to the electric garden tool. Thus, the second battery pack may be charged while the first battery pack is in use. When the first battery pack is depleted, the second battery pack may be removed from the mobile charging device and connected to the tool. The first battery pack may then be connected to the mobile charging device and charged while the second battery pack is in use. In some embodiments, the mobile charging device is configured to provide sufficient electrical energy for multiple operations. For example, the minimum output power of the mobile charging device is greater than 3600W, and the battery pack may be charged at a charging rate of 5C. In some cases, the mobile charging device may provide up to 12 hours of power on a single charge.

[0132] In some embodiments, the mobile charging device can operate in a first charging mode and / or a second charging mode. The first charging mode includes a charging output of approximately 3.6 kW and a charging rate of no more than 10C for a 4Ah battery pack or a charging rate greater than 4C for an 11Ah battery pack. When in the second charging mode, the output power of the mobile charging device can reach 7.2 kW, and the charging rate for an 11Ah battery pack does not exceed 10C. In some examples, the output power of the mobile charging device is greater than or equal to 3.6 kW, and the rated power of any one of the multiple power tools is less than or equal to 3 kW.

[0133] Therefore, the mobile charging device has at least two charging modules, a single charging module outputs 3.6kW, and multiple parallel single modules output greater than 7.2kW. Therefore, when in the first charging mode, the charging modules work independently, and when in the second charging mode, multiple single modules work in parallel.

[0134] In addition, when the battery pack is connected to the mobile charging device, the mobile charging device includes logic for determining the capacity of the connected battery pack. The mobile charging device can then determine what power to provide to the battery pack, for example, 3.6kW (e.g., the first charging mode) or 7.2kW (e.g., the second charging mode).

[0135] In other embodiments, there may be a user-operated switch on the mobile charging device to manually switch from the first charging mode to the second charging mode. Optionally, there may be a user-operated switch that, when activated, causes the mobile charging device to check the charging power requirement from the battery pack. If the current charging power is suitable for the connected battery pack, the charging mode will be the first charging mode that supplies 3.6kW. Otherwise, the charging mode will switch from the first charging mode to the second charging mode to provide greater power (e.g., 7.2kW).

[0136] The energy density of the battery cell in the mobile charging device is greater than the energy density of the battery pack, and the capacity of the mobile charging device is greater than the capacity of the battery pack. Therefore, the energy ratio between the mobile charging device and the battery pack is greater than 3. Therefore, the weight ratio between the battery cell in the mobile charging device and the battery cell in the battery pack is less than the capacity ratio. For example, the weight of the second battery pack may be less than 3.5kg and the capacity may be about 3.6Ah to about 4Ah, the weight of the first battery pack may be less than 8kg and the capacity may be about 8Ah to about 11Ah, and the weight of the mobile charging device may be less than 130kg and the capacity may be at least 100Ah. The capacity of the second battery pack may be less than the capacity of the first battery pack, the first battery pack and the second battery pack may have the same capacity, or the second battery pack may have a lower capacity than the first battery pack. Any suitable capacity configuration is acceptable. In some cases, the maximum life cycle of the battery cell of the mobile charging device may be less than the maximum life cycle of the battery cell of the battery pack. Therefore, the ratio of the life cycle of the battery cell of the battery pack to the life cycle of the battery cell of the mobile charging device is greater than 3. This means that the maximum life cycle of the mobile charging device is less than the maximum life cycle of the battery pack, and the ratio of the life cycle of the battery pack to the life cycle of the mobile charging device is greater than 3.

[0137] In a preferred embodiment, the mobile charging device is configured to determine the charging power required for the battery pack based on the capacity of the battery pack, and switch between the first and second charging modes based on the charging power determined to be required. For example, when a 4Ah battery is connected, the mobile charging device can operate in the first charging mode. On the other hand, when an 11Ah battery pack is connected, the mobile charging device can operate in the second charging mode, providing 7.2kW of power.

[0138] In an optional example, the battery pack may have a continuous discharge power in the range of about 0.4 kW to about 1.5 kW for at least 8 minutes, and the internal resistance of the battery cell may be less than or equal to 1 milliohm.

[0139] Furthermore, the provided battery pack not only has a large charge and discharge rate, but also has a low temperature rise characteristic during the high rate charge and high rate discharge of the battery pack. In addition, the battery pack is charged faster than it is discharged.

[0140] Specifically, the charging device of the battery pack is provided with a cooling fan, which is configured to start when the battery pack is charged to drive airflow to cool the battery pack, and to shut down when charging is finished. In this embodiment, when the cooling fan is started, the output power of the cooling fan is greater than 5W and less than 7W, the rated speed is greater than 2000rpm, and the air volume of the cooling fan is greater than 24 cubic feet per minute (FCM) and less than 30FCM, thereby having a relatively good cooling effect. Figure 5B and Figure 5DAs shown, since the single cells in the battery pack are sheet cells, and there is a gap between adjacent batteries along the thickness direction of the single cells, a heat dissipation duct can be formed between two adjacent cells. When the cooling fan is started, it can drive the air flow in the heat dissipation duct to dissipate the heat on the surface of the single cell. And since the single cell is a sheet cell, the heat dissipation area is large, which can improve the heat dissipation effect. In one example, the cell used in any disclosed battery pack can be called a Type 2 cell, which can be obtained from Suzhou Aimeide New Energy Materials Co., Ltd., No. 9 Haixin South Road, Nanfeng Town, Zhangjiagang City, Jiangsu Province, China.

[0141] When the cooling fan of the charging device is not started, and the battery pack provided in the present application is charged at a continuous charging rate greater than or equal to 3C and less than or equal to 6C at room temperature (approximately 25°C, with a deviation of approximately ±3°C), the temperature rise on the surface of the battery pack is greater than or equal to 6°C and less than or equal to 15°C; when the battery pack is charged at a continuous charging rate greater than or equal to 6C and less than or equal to 8C at room temperature, the temperature rise on the surface of the battery pack is greater than or equal to 15°C and less than or equal to 25°C; when the battery pack is charged at a continuous charging rate greater than or equal to 8C and less than or equal to 12C at room temperature, the temperature rise on the surface of the battery pack is greater than or equal to 25°C and less than or equal to 35°C.

[0142] When the charging device starts the cooling fan, when the battery pack provided in the present application is charged at a continuous charging rate greater than or equal to 3C and less than or equal to 6C at room temperature, the temperature rise on the surface of the battery pack is greater than or equal to 3°C and less than or equal to 12°C; when the battery pack is charged at a continuous charging rate greater than or equal to 6C and less than or equal to 8C at room temperature, the temperature rise on the surface of the battery pack is greater than or equal to 12°C and less than or equal to 21°C; when the battery pack is charged at a continuous charging rate greater than or equal to 8C and less than or equal to 12C at room temperature, the temperature rise on the surface of the battery pack is greater than or equal to 21°C and less than or equal to 33°C.

[0143] When the cooling fan of the traditional 21700 lithium iron phosphate system battery pack is started by the charging device, the temperature rise of the battery pack reaches 14°C when charged at a charging rate of 2C at room temperature. The temperature rise performance of the traditional 18650 lithium battery system battery pack is worse than that of the 21700 lithium iron phosphate system battery pack. When these two types of battery packs are charged at a continuous charging rate greater than 3C, the temperature rise has reached the charging protection temperature value of the battery pack. Therefore, these two types of battery packs are usually charged at a charging rate less than or equal to 2C. When the cooling fan is not started in the charging device, the battery pack provided by the present application has a temperature rise of only 6°C when charged at a continuous charging rate of 3C, which is lower than the temperature rise of the traditional 18650 lithium battery system battery pack and the 21700 lithium iron phosphate system battery pack when the cooling fan is started in the charging device. When the cooling fan is started in the charging device, the temperature rise of the battery pack of the present application is only 3°C when charged at a continuous charging rate of 3C, which is much lower than the temperature rise of the 21700 lithium iron phosphate system battery pack and the 18650 lithium battery system battery pack when the charging rate is continuously charged at a 2C charging rate. And even if the battery pack of the present application is charged at a continuous charging rate of 12C, the temperature rise of the battery pack still does not reach the temperature protection value when the cooling fan is not turned on in the charging device. It can be seen that the battery pack of the present application not only has a large charging rate, but also has a low temperature rise when charged at a large rate, which is conducive to supporting the uninterrupted cycle operation of the battery pack.

[0144] The battery pack of the present application has a low temperature rise not only during charging, but also during discharging. Specifically, when the battery pack is discharged at a continuous discharge rate of 3C or more and 4C or less at room temperature, the temperature rise on the surface of the battery pack is greater than or equal to 10°C and less than or equal to 15°C; when the battery pack is discharged at a continuous discharge rate of 4C or more and 10C or less at room temperature, the temperature rise on the surface of the battery pack is greater than or equal to 15°C and less than or equal to 35°C.

[0145] As a specific example, when the charging device starts the cooling fan, if the first type battery pack 101 is charged at a continuous charging rate of 3C at room temperature, the temperature rise of the battery pack is 6°C, and if the first type battery pack 101 is charged at a continuous charging rate of 6C at room temperature, the temperature rise of the battery pack is 15°C. If the second type battery pack 102 is continuously charged at a charging rate of 12C at room temperature, the temperature rise of the battery pack is 35°C.

[0146] When the charging device starts the cooling fan, if the first type battery pack 101 is charged at a continuous charging rate of 3C at room temperature, the temperature rise of the battery pack is 3°C, if the first type battery pack 101 is charged at a continuous charging rate of 4C at room temperature, the temperature rise of the battery pack is 10°C, if the first type battery pack 101 is charged at a continuous charging rate of 6C at room temperature, the temperature rise of the battery pack is 12°C. If the second type battery pack 102 is charged at a continuous charging rate of 8C at room temperature, the temperature rise of the battery pack is 21°C, if the second type battery pack 102 is charged at a continuous charging rate of 12C at room temperature, the temperature rise of the battery pack is 33°C.

[0147] When the first type battery pack 101 is discharged at a continuous discharge rate of 3C at room temperature, the temperature rise of the battery pack is 10°C. When the first type battery pack 101 is discharged at a continuous discharge rate of 4C at room temperature, the temperature rise of the battery pack is 15°C. When the second type battery pack is discharged at a continuous discharge rate of 10C at room temperature, the temperature rise of the battery pack is 35°C.

[0148] Therefore, the battery pack has a low temperature rise during high-rate charge and discharge. After discharge, due to the low temperature rise, charging can be started immediately without waiting, or after charging, due to the low temperature rise, discharging can be started immediately without waiting.

[0149] Specifically, when the cooling fan of the charging device is not turned on, at room temperature, when the battery pack is charged and discharged at a charge rate of 3C and a discharge rate of 4C, the curves of its surface temperature and voltage changing with time are as follows: Fig.12 As shown. The dotted line is the curve of the battery pack voltage changing with the charge and discharge time, and the solid line is the curve of the battery pack surface temperature changing with the charge and discharge time. The process of the battery pack being fully charged from 0 to 100%, and then discharged from 100% to 0 is a single charge and discharge cycle of the battery pack. It can be seen from the voltage curve that the voltage of the battery pack increases during the period from 0 to t1, at which time the battery pack is in a charging state, and the voltage of the battery pack decreases during the period from t1 to t2, at which time the battery pack is in a discharging state. As shown Figure 6As shown, at time 0, the battery pack has not started charging, and the surface temperature is the same as the room temperature, that is, 25°C. When charging is completed (time t1), the surface temperature of the battery pack rises to 28.1°C. Since the charging protection temperature of the battery pack is 60°C, the surface temperature of the battery pack does not reach the charging protection temperature after charging is completed, and the battery pack may be discharged directly without waiting. At time t2, when the discharge is completed, the surface temperature of the battery pack rises to 40°C. Since the discharge protection temperature of the battery pack is 70°C, the surface temperature of the battery pack does not reach the discharge protection temperature value of the battery pack at the end of a single charge and discharge cycle of the battery pack. The battery pack will not perform discharge protection, and it has not reached the charging protection temperature value of the battery pack, so the battery pack can continue to charge uninterruptedly. In summary, this embodiment provides a battery pack, even if the charging device does not turn on the cooling fan during charging, the battery pack can start the next charge and discharge cycle immediately after a single charge and discharge cycle ends without waiting.

[0150] When the charging device turns on the cooling fan, at room temperature, the battery pack is charged and discharged at a 3C charge rate and a 3C discharge rate for a single charge and discharge cycle. The curves of the temperature and voltage of the battery pack changing with time are shown in Figure 7 . Among them, the voltage of the battery pack increases during the period 0 to t1, at which time the battery pack is in a charging state, and the voltage of the battery pack decreases during the period t1 to t2, at which time the battery pack is in a discharging state. At the end of charging at time t1, the surface temperature of the battery pack is 26.1°C. Since the charging protection temperature of the battery pack is 60°C, the surface temperature of the battery pack is low after a single charge, and it can be discharged directly without waiting. At the end of the discharge of the battery pack at time t2, the surface temperature of the battery pack is 39.1°C. Since the discharge protection temperature of the battery pack is 70°C, the discharge protection temperature value of the battery pack is not reached, and the battery pack will not perform discharge protection, and the charging protection temperature value of the battery pack is not reached, so the battery pack can continue to charge without interruption. Under the condition of wind cooling, the surface temperature of the battery pack at the end of a single charge and discharge cycle at a charging rate of 3C and a discharge rate of 3C is less than 40°C. Due to the low temperature, the battery pack can continue to charge and discharge without interruption.

[0151] Furthermore, when the cooling fan of the charging device is not turned on, at room temperature, when the battery pack is charged and discharged multiple times at a charging rate of 3C and a discharging rate of 4C, the curves of the surface temperature and voltage of the battery pack changing with time are as follows: Figure 8 As shown. The dotted line is the curve of the battery pack voltage changing with the charge and discharge time, and the solid line is the curve of the battery pack surface temperature changing with the charge and discharge time. The process of the battery pack immediately starting the next charge and discharge cycle without interval after the end of a single charge and discharge cycle is the multiple charge and discharge cycle process of the battery pack.

[0152] The nominal voltage of the battery pack of the present application is 60V, and its actual voltage is 62.25V. Each battery pack is composed of 15 single cells connected in series, and the actual voltage of each single cell is 4.15V. Figure 8 , the process of the battery pack voltage rising from 42.4V to 62.25V is the charging process, and the process of the battery pack voltage decreasing from 62.25V to 42.4V is the discharging process. Among them, the period from 0 to t1 is the first charging process, and the period from t1 to t2 is the first discharging process, that is, the period from 0 to t2 is the first charge and discharge cycle process. At t2, the surface temperature A of the battery pack is 40°C at the end of the first charge and discharge cycle, so the temperature rise of the first charge and discharge cycle is 15°C. Since the charging protection temperature of the battery pack is 60°C, the surface temperature of the battery pack does not reach the charging protection temperature after the first charge and discharge cycle, and the next charge and discharge cycle can be carried out directly without waiting. The period from t2 to t3 is the second charging process, and the period from t3 to t4 is the second discharging process, that is, the period from t2 to t4 is the second charge and discharge cycle process. At t4, the surface temperature B of the battery pack is 52°C at the end of the second charge and discharge cycle. Since the charging protection temperature of the battery pack is 60℃, the surface temperature of the battery pack has not reached the charging protection temperature after the second charge and discharge cycle, and the next charge and discharge cycle can be carried out directly. The period from t4 to t5 is the third charging process, and the period from t5 to t6 is the third discharging process, that is, the period from t4 to t6 is the third charge and discharge cycle process. At time t6, the surface temperature C of the battery pack is 60℃ at the end of the third charge and discharge cycle. Since the charging rate and discharge rate of the battery pack are the same during each charge and discharge cycle, the charging time and discharge time in each cycle are the same, so the time of each charge and discharge cycle of the battery pack is equal, that is, t2=t4-t2=t6-t4.

[0153] In summary, when the cooling fan of the charging device is not turned on, the battery pack can maintain three uninterrupted charge and discharge cycles at a charge rate of 3C and a discharge rate of 4C. After three cycles, the temperature of the battery pack reaches the charging temperature protection value.

[0154] When the traditional lithium battery system 18650 battery pack is charged and discharged at a charge rate of 3C and a discharge rate of 4C, the charging protection is turned on after one cycle, resulting in the battery pack being unable to carry out the next round of charge and discharge cycles uninterruptedly. The reason why the battery pack of the present application can maintain three uninterrupted charge and discharge cycles without turning on the cooling fan of the charging device is that, on the one hand, the battery pack has good temperature rise performance and a slow temperature rise rate; on the other hand, the charging protection temperature value of the battery pack is higher than that of the traditional battery pack, and the charging protection temperature value of the battery pack of the present application is 60°C. Due to the good temperature rise performance, the surface temperature is far from reaching the charging protection temperature value after the charging and discharging is completed, so charging can continue after the charging and discharging superposition process; however, the charging protection temperature of the traditional 18650 system battery pack is 60°C (the discharge protection temperature is 80°C). Due to the high temperature rise of the 18650 lithium battery system battery pack, the traditional 18650 lithium battery system battery pack needs to wait for the battery pack to cool down after charging and discharging once at a charging rate of 3C and a discharge rate of 4C.

[0155] In actual use, the charging and cooling fan of the charging device will start during charging, so the battery pack will be cooled during the charging process, so that the battery pack can support longer uninterrupted charge and discharge cycles. In this embodiment, when the battery pack is charged and discharged at room temperature with a charge rate of not less than 3C and a discharge rate of not less than 3C, it can maintain at least 6 uninterrupted charge and discharge cycles.

[0156] As an example, Fig. 9 When the cooling fan of the charging device is started, at room temperature, the battery pack is continuously charged and discharged at a charging rate of 3C and a discharge rate of 3C, and the curve of the battery pack surface temperature and battery pack voltage changes with the charge and discharge time. Fig. 9 As shown, the process of the voltage rising from 42.4V to 62.7V is the charging process of the battery pack, and the process of the voltage dropping from 62.7V to 42.4V is the discharging process of the battery pack. The period from 0 to t1 is the first charging process, and the period from t1 to t2 is the first discharging process, that is, the period from 0 to t2 is the first charge and discharge cycle process. At time t2, the surface temperature A of the battery pack is 39.1°C at the end of the first charge and discharge cycle. Since the surface temperature of the battery pack at time 0 is the same as the room temperature, that is, 25°C, the temperature rise of the battery pack during the first charge and discharge cycle is 39.1°C-25°C=14.1°C;

[0157] The period from t2 to t3 is the second charging process, and the period from t3 to t4 is the second discharging process, that is, the period from t2 to t4 is the second charge and discharge cycle process. At time t4, the surface temperature B of the battery pack at the end of the second charge and discharge cycle is 42.2°C. Therefore, the temperature rise of the battery pack during the second charge and discharge cycle is 42.2°C-39.1°C=3.1°C;

[0158] The period from t4 to t5 is the third charging process, and the period from t5 to t6 is the third discharging process, that is, the period from t4 to t6 is the third charge-discharge cycle process. At time t6, the surface temperature C of the battery pack is 43.4°C at the end of the third charge-discharge cycle. Therefore, the temperature rise of the battery pack during the third charge-discharge cycle is 43.4°C-42.2°C=1.2°C.

[0159] The period from t6 to t7 is the fourth charging process, and the period from t7 to t8 is the fourth discharging process, that is, the period from t6 to t8 is the fourth charge and discharge cycle process. At time t8, the surface temperature D of the battery pack is 44.1°C at the end of the fourth charge and discharge cycle. Therefore, the temperature rise of the battery pack during the fourth charge and discharge cycle is 44.1°C-43.4°C=0.7°C.

[0160] The period from t8 to t9 is the fifth charging process, and the period from t9 to t10 is the fifth discharging process, that is, the period from t8 to t10 is the fifth charge and discharge cycle process. At time t10, the surface temperature E of the battery pack is 44.4°C at the end of the fifth charge and discharge cycle. Therefore, the temperature rise of the battery pack during the fifth charge and discharge cycle is 44.4°C-44.1°C=0.3°C.

[0161] The period from t10 to t11 is the sixth charging process, and the period from t11 to t12 is the sixth discharging process, that is, the period from t10 to t12 is the sixth charge and discharge cycle process. At t12, the surface temperature F of the battery pack is 45.1°C at the end of the sixth charge and discharge cycle. Therefore, the temperature rise of the battery pack during the sixth charge and discharge cycle is 45.1°C-44.4°C=0.7°C. After the six charge and discharge cycles, the surface temperature of the battery pack is 45°C, which still does not reach the charging temperature protection value and the discharging temperature protection value of the battery pack.

[0162] like Fig. 9As shown, during the first charging process, the temperature of the battery pack rises, and during the second to sixth charging processes, the temperature of the battery pack decreases. This is because during the charging process, the temperature of the battery pack rises due to the chemical reaction inside the battery cell, generating heat Q1. Since the temperature of the battery pack is higher than the ambient temperature, the battery pack will dissipate heat to the environment, and the heat dissipated is Q2. The heat dissipated by the battery pack due to the cooling device being turned on during the charging process is Q3. During the first charging, the base temperature of the battery pack is low, and thus the heat Q2 dissipated by the battery pack to the environment and the heat Q3 dissipated by the battery pack due to the cooling fan being turned on are both small. The heat dissipated by the battery pack is less than the heat generated by the battery pack, that is, Q2+Q3<Q1, causing the overall temperature of the battery pack to rise during the first charging process. During the first discharge process, since there is no cooling device, the battery pack can only dissipate heat by exchanging heat with the environment. The heat dissipation rate is slow, and the battery pack temperature rises, resulting in a higher base temperature and faster heat dissipation rate during the second charge. As a result, the heat Q2 dissipated by the battery pack to the environment and the heat Q3 dissipated by the battery pack due to the cooling fan being turned on are both large. The heat dissipated by the battery pack is greater than the heat generated by the battery pack, that is, Q2+Q3>Q1. Therefore, in the subsequent cycles, the temperature of the battery pack shows a downward trend during the charging process.

[0163] In addition, during each cycle of charging, the time when the battery pack voltage rises to the highest point does not overlap with the time when the battery pack temperature drops to the lowest point, and the time when the battery pack temperature drops to the lowest point lags behind the time when the battery pack voltage rises to the highest point. Fig. 9 As shown, in the second charging process, the moment when the battery pack voltage rises to the highest point is t3, and the moment when the battery pack temperature drops to the lowest point is t3', and t3' lags behind t3; in the third charging process, the moment when the battery pack voltage rises to the highest point is t5, and the moment when the battery pack temperature drops to the lowest point is t5', and t5' lags behind t5. The other charging processes are similar. This is because the temperature of the battery pack will not change suddenly after the charging is completed and the discharging begins. At the initial moment of the discharge, the temperature of the battery pack will continue the trend of decreasing temperature. As the heat generated by the battery pack increases during the discharge process, the temperature of the battery pack will gradually rise. Therefore, the charging end time of the battery pack is based on the moment when the battery pack voltage rises to the highest point.

[0164] Depend on Fig. 9 As shown, when the charging device starts the cooling fan, the battery pack can be charged and discharged continuously at a charging rate of 3C and a discharging rate of 3C for at least 6 uninterrupted charge and discharge cycles. Since the battery pack has the same charge and discharge rate each time, the duration of each charge and discharge cycle of the battery pack is the same.

[0165] As another example, Fig.10When the charging device starts the cooling fan, at room temperature (25°C), the battery pack is continuously charged and discharged at a charging rate of 4C and a discharge rate of 4C. The curve of the battery pack surface temperature and battery pack voltage changes with the charge and discharge time. Fig.10 It can be seen that the battery pack can perform at least 6 uninterrupted charge and discharge cycles at a charge and discharge rate of 4C. Among them, the period from 0 to t1 is the first charging process, and the period from t1 to t2 is the first discharging process, that is, the period from 0 to t2 is the first charge and discharge cycle process. At time t2, the surface temperature A of the battery pack at the end of the first charge and discharge cycle is 44.2°C. Since the surface temperature of the battery pack at time 0 is the same as the room temperature, that is, 25°C, the temperature rise of the battery pack during the first charge and discharge cycle is 44.2°C-25°C=19.2°C;

[0166] The period from t2 to t3 is the second charging process, and the period from t3 to t4 is the second discharging process, that is, the period from t2 to t4 is the second charge and discharge cycle process. At time t4, the surface temperature B of the battery pack at the end of the second charge and discharge cycle is 49.9°C. Therefore, the temperature rise of the battery pack during the second charge and discharge cycle is 49.9°C-44.2°C=5.7°C;

[0167] The period from t4 to t5 is the third charging process, and the period from t5 to t6 is the third discharging process, that is, the period from t4 to t6 is the third charge-discharge cycle process. At time t6, the surface temperature C of the battery pack is 52°C at the end of the third charge-discharge cycle. Therefore, the temperature rise of the battery pack during the third charge-discharge cycle is 52°C-49.9°C=2.1°C.

[0168] The period from t6 to t7 is the fourth charging process, and the period from t7 to t8 is the fourth discharging process, that is, the period from t6 to t8 is the fourth charge and discharge cycle process. At time t8, the surface temperature D of the battery pack is 52.7°C at the end of the fourth charge and discharge cycle. Therefore, the temperature rise of the battery pack during the fourth charge and discharge cycle is 52.7°C-52°C=0.7°C.

[0169] The period from t8 to t9 is the fifth charging process, and the period from t9 to t10 is the fifth discharging process, that is, the period from t8 to t10 is the fifth charge and discharge cycle process. At time t10, the surface temperature E of the battery pack is 53.1°C at the end of the fifth charge and discharge cycle. Therefore, the temperature rise of the battery pack during the fifth charge and discharge cycle is 53.1°C-52.7°C=0.4°C.

[0170] The period from t10 to t11 is the sixth charging process, and the period from t11 to t12 is the sixth discharging process, that is, the period from t10 to t12 is the sixth charge and discharge cycle process. At t12, the surface temperature F of the battery pack is 53.6°C at the end of the sixth charge and discharge cycle. Therefore, the temperature rise of the battery pack during the sixth charge and discharge cycle is 53.6°C-53.1°C=0.5°C. After the six charge and discharge cycles, the surface temperature of the battery pack is 53.6°C, which has not yet reached the charging temperature protection value and the discharge temperature protection value of the battery pack. Therefore, the battery pack can maintain at least six uninterrupted charge and discharge cycles at room temperature with a charge rate of 4C and a discharge rate of 4C.

[0171] As another example, Fig.11 When the charging device starts the cooling fan, at room temperature (25°C), the battery pack is continuously charged and discharged at a charging rate of 6C and a discharge rate of 4C. The curve of the battery pack surface temperature and battery pack voltage changes with the charge and discharge time. Fig.11 It can be seen that the battery pack can be charged and discharged for at least 6 times without interruption when it is charged and discharged at a charging rate of 6C and a discharging rate of 4C. Among them, the period from 0 to t1 is the first charging process, and the period from t1 to t2 is the first discharging process, that is, the period from 0 to t2 is the first charging and discharging cycle process. At time t2, the surface temperature A of the battery pack is 45°C at the end of the first charging and discharging cycle. Since the surface temperature of the battery pack at time 0 is the same as the room temperature, that is, 25°C, the temperature rise of the battery pack during the first charging and discharging cycle is 45°C-25°C=20°C;

[0172] The period from t2 to t3 is the second charging process, and the period from t3 to t4 is the second discharging process, that is, the period from t2 to t4 is the second charge and discharge cycle process. At time t4, the surface temperature B of the battery pack at the end of the second charge and discharge cycle is 50°C. Therefore, the temperature rise of the battery pack during the second charge and discharge cycle is 49.9°C-50°C-45°C=5°C;

[0173] The period from t4 to t5 is the third charging process, and the period from t5 to t6 is the third discharging process, that is, the period from t4 to t6 is the third charge-discharge cycle process. At time t6, the surface temperature C of the battery pack is 52°C at the end of the third charge-discharge cycle. Therefore, the temperature rise of the battery pack during the third charge-discharge cycle is 52°C-50°C=2°C.

[0174] The period from t6 to t7 is the fourth charging process, and the period from t7 to t8 is the fourth discharging process, that is, the period from t6 to t8 is the fourth charge and discharge cycle process. At time t8, the surface temperature D of the battery pack is 53°C at the end of the fourth charge and discharge cycle. Therefore, the temperature rise of the battery pack during the fourth charge and discharge cycle is 53°C-52°C=1°C.

[0175] The period from t8 to t9 is the fifth charging process, and the period from t9 to t10 is the fifth discharging process, that is, the period from t8 to t10 is the fifth charge-discharge cycle process. At time t10, the surface temperature E of the battery pack is 54°C at the end of the fifth charge-discharge cycle. Therefore, the temperature rise of the battery pack during the fifth charge-discharge cycle is 54°C-53°C=1°C.

[0176] The period from t10 to t11 is the sixth charging process, and the period from t11 to t12 is the sixth discharging process, that is, the period from t10 to t12 is the sixth charge and discharge cycle process. At t12, the surface temperature F of the battery pack is 55°C at the end of the sixth charge and discharge cycle. Therefore, the temperature rise of the battery pack during the sixth charge and discharge cycle is 55°C-54°C=1°C. After the six charge and discharge cycles, the surface temperature of the battery pack is 55°C, which still does not reach the charging temperature protection value and the discharge temperature protection value of the battery pack. Therefore, the battery pack can maintain at least 6 uninterrupted charge and discharge cycles at room temperature with a charge rate of 6C and a discharge rate of 4C.

[0177] In addition, the state of charge-open circuit voltage (SOC-OCV) curve of each cell of the battery pack provided by the present application has a quasi-linear characteristic, that is, the SOC-OCV curve of each cell of the battery pack is approximately a linear curve. OCV is the open circuit voltage of the battery cell, and SOC is the state of charge of each cell of the battery pack, that is, the current capacity of each cell of the battery pack accounts for the percentage of the rated capacity of each cell of the battery pack.

[0178] The SOC-OCV curve of each battery cell of the battery pack satisfies the following relationship: when the resolution of SOC in the SOC-OCV curve is 5%, in each 5% SOC interval, the slope k of the SOC-OCV curve is not less than 0.8, where k = ΔOCV / ΔSOC, where ΔSOC is the difference in the state of charge between two adjacent points, and ΔOCV is the difference in the open circuit voltage between the corresponding two adjacent points; and in each two adjacent 5% SOC intervals, the absolute value of the slope change Δk of the SOC-OCV curve is not greater than 0.2, where Δk = kn+1-kn, kn+1 and kn are the slopes of the SOC-OCV curve in two adjacent 5% SOC intervals, respectively. Considering the test error, ΔK is not greater than 0.2±0.05.

[0179] The SOC-OCV curve of the traditional 18650 battery pack has a distinct voltage platform. Specifically, in the middle section of the SOC-OCV curve, the open circuit voltage OCV hardly changes with the change of SOC, so at the end of the SOC-OCV curve, the curve slope changes less, and in the front and back sections of the SOC-OCV curve, the OCV changes in a larger range and the curve slope changes more.

[0180] Fig.12 The SOC-OCV data variation range of the battery pack and 18650 type battery pack provided in this application, among which TYPE2 is the battery pack provided in this application:

[0181] The method for obtaining SOC-OCV data is to take a value of the SOC of the battery pack provided in this application and the traditional 18650 battery pack at intervals of 5% from 0 to 100% as the measured value. Taking the discharge test as an example, the open circuit voltage is measured every time the SOC of the battery pack decreases by 5%. It should be noted that after the SOC of the battery pack decreases by 5%, the battery pack is left to stand for a period of time until the battery pack is completely uncharged, and then the open circuit voltage OCV of the two battery packs is measured respectively. It should also be noted that only the battery discharge data is close to the linear characteristic, and the charging is not linear.

[0182] According to the data table shown in the table above, the SOC-OCV curves of the battery pack of the present application and the 18650 type battery pack can be fitted. Fig.12 As shown, when the open circuit voltage is 3.25V (3.249V), the SOC of the 18650 battery cell reaches 0 (i.e., the battery pack is exhausted). However, when the open circuit voltage is 3.25V, the SOC of each battery cell of the provided battery pack is still not less than 20%. Therefore, each battery cell of the battery pack provided in the present application has a greater capacity retention rate below the low voltage range (3.25V). When the open circuit voltage is about 3.66V, the SOC of each battery cell of the provided battery pack and the 18650 battery cell are close to 50%. In the voltage segment above 3.66V, the voltage platform of each battery cell of the battery pack of the present application is higher. In the voltage segment below 3.66V, the voltage platform of the 18650 battery pack cell is higher.

[0183] Fig.13 Based on Fig.21 The slope k variation curve obtained by fitting the SOC-OCV curve of the two battery packs shown in FIG. 1 , wherein each slope sampling point is the slope of the SOC-OCV curve within each 5% SOC interval. Fig.13As shown, the slope range of each battery cell of the battery pack provided by the present application is greater than or equal to 0.8. When the SOC of each battery cell of the battery pack is 0-30% of the rated capacity of each battery cell of the battery pack, the slope range of the SOC-OCV curve of each battery cell of the battery pack is 2.06-1.56. When the SOC of each battery cell of the battery pack is 30%-65% of the rated capacity of each battery cell of the battery pack, the slope range of the SOC-OCV curve of each battery cell of the battery pack is between 1.56 and 1.14. When the SOC of each battery cell of the battery pack is 65% to 100% of the rated capacity of each battery cell of the battery pack, the slope range of the SOC-OCV curve of each battery cell of the battery pack is 1.14-0.92. However, in traditional 18650-type batteries, the SOC of the battery cell is 0-30% of the rated capacity of the battery cell, and the slope range of the SOC-OCV curve of the battery cell is 2.02-0.72. When the SOC of the battery cell is 30%-65% of the rated capacity of the battery cell, the slope of the SOC-OCV curve of the battery cell ranges from 0.72-1. When the SOC of the battery cell is 65%-100% of the rated capacity of the battery cell, the slope of the SOC-OCV curve of the battery cell ranges from 1-1.2. Specifically, when the SOC of the battery cell is 30%-65% of the rated capacity of the battery cell, the slope of the SOC-OCV curve of each battery cell of the provided battery pack continuously decreases from 1.56 to 1.14, while the slope of the SOC-OCV curve of the traditional 18650 type battery cell first remains at 0.72, decreases from 0.72 to 0.33, and then increases from 0.33 to 1. Therefore, the slope of the SOC-OCV curve of the battery cell of the battery pack provided in the present application is closer to a linear curve than the traditional 18650.

[0184] Fig.14 Based on Fig.13 The slope change curve is obtained by fitting the slope curve shown in FIG. The slope change is the change in the slope within two adjacent 5% SOC intervals. Fig.14As shown, the SOC-OCV curve of each battery cell of the battery pack provided by the present application has a slope change of less than 0.2 in each two adjacent 5% SOC intervals. However, for the traditional 18650 battery pack, the slope change of the SOC-OCV curve is relatively large in different SOC intervals. Specifically, the slope change reaches 1.3 between SOC of 5%-10% and SOC of 10%-15%, and the slope change is -0.4 between SOC of 55%-60% and SOC of 60%-65%, and the slope of the SOC-OCV curve varies greatly at different places. It can be seen from this that the slope change of the SOC-OCV curve of each battery cell of the battery pack of the present application is smaller than that of the traditional 18650 battery cell, and the SOC-OCV curve of each battery cell of the battery pack described herein is close to a linear curve. When predicting the remaining power, each cell of the battery pack of the present application can be predicted with relatively high accuracy based on its SOC-OCV curve. However, the SOC-OCV curve of the traditional 18650 cell is not a reference for predicting the power.

[0185] The aforementioned SOC-OCV data is the test data of the battery cell at a discharge rate of 10C. It can be seen from the aforementioned data that when discharged at a rate of 10C, the change △K of the slope K at two adjacent sampling points of the Type2 battery cell is less than 0.2, and the SOC change of the two adjacent sampling points is 5%. It should be emphasized here that as the discharge rate decreases, the SOC-OCV curve changes more gently, making the slope K at each sampling point smaller, so that the difference in the slope K between two adjacent sampling points will become smaller. In other words, as the discharge rate decreases, the difference in the slope K at two adjacent sampling points of the Type2 battery cell decreases, making the linear characteristics of the Type2 battery cell more obvious. Each Type2 battery cell has obvious linear characteristics, so that the battery pack composed of Type2 batteries also has obvious linear characteristics.

[0186] In at least one embodiment, the battery cells in the battery pack have linear characteristics as described above. In addition, the charging rate of the battery cells is greater than 5C, and the energy density of the battery cells is greater than 120Wh / kg. In other embodiments, the charging rate of the battery cells may also be the values ​​listed in other embodiments. Optionally, the energy density of the battery is greater than 125Wh / kg, or 130Wh / kg, or 135Wh / kg.

[0187] Fig.15 A comparison between the 18650 cell and the cell described in this article is shown. Fig.15As shown, the discharge is performed at 5C and 10C rates. During the discharge process, the voltage of an 18650 battery cell changes greatly at the beginning and end of the discharge, and the voltage changes less during the discharge process, which makes the voltage change during the entire discharge process more inclined to an S-shaped curve. In contrast, the voltage of the battery pack described herein (for example, 4Ah of Type2 at a 5C discharge rate and 4Ah of Type2 at a 10C discharge rate) is substantially linear throughout the discharge process. The battery discharge slope range described herein is about 0.05V / s to about 0.2V / s (for example, about 0.07V / s to about 0.19V / s, about 0.09V / s to about 0.15V / s, or about 0.12V / s). In other words, compared to the example 18650 battery, the rate at which the voltage changes over time is relatively constant. According to another aspect, the voltage change changes with the change in the discharge rate. The greater the discharge rate, the greater the change in voltage.

[0188] Currently, the power of most garden power tools is 1800W~2400W, and the nominal voltage of the battery pack provided in this application is 60V. Therefore, when the discharge current of the first type of battery pack (11Ah) reaches 30A~40A, it can meet the power demand of the garden power tool, that is, the first type of battery pack can meet the power demand of the garden power tool when it is continuously discharged at a discharge rate of 3C or a discharge rate of 4C.

[0189] When a first-class battery pack works continuously at a charge rate of 3C and a discharge rate of 3C, it can maintain at least 6 uninterrupted charge and discharge cycles. Among them, the battery pack charges for 20 minutes each time, discharges for 20 minutes each time, and the single charge and discharge time is 40 minutes. A first-class battery pack can maintain uninterrupted charge and discharge for at least 240 minutes when working at a charge and discharge rate of 3C. Two first-class battery packs can be used alternately to achieve 240 minutes (4 hours) of uninterrupted power supply, one of which is a working battery pack and the other is a backup battery pack. When the working battery pack is discharging, the backup battery pack is charging. When the working battery pack is discharged, the backup battery pack is fully charged. The backup battery pack can be installed on the power tool for use when the working battery pack is charging.

[0190] In actual use, power tools are not always in working condition. For example, when transferring from one garden to another or when the staff is resting, the power tools are stopped. The battery pack can use the power tool stop time to cool down, so that when the battery pack starts charging or discharging again, the starting temperature is lower, and the surface temperature is also lower after charging or discharging. Under the same temperature protection threshold conditions, the number of cycles of the battery pack can be increased, and the working time of the battery pack can be increased. Therefore, for the garden team, two first-class battery packs working at a charge and discharge rate of 3C can maintain an electric tool working uninterruptedly for half a day, and after half a day's work, the two battery packs can use the lunch break to cool down, so that the starting temperature of the battery pack returns to room temperature during the afternoon work, so that the two battery packs can continue to work alternately for at least 4 hours. Therefore, for an electric tool, two first-class battery packs with a charging rate of 3C and a discharge rate of 3C can maintain a day's work.

[0191] Similarly, when the first type of battery pack works continuously at a charging rate of 4C and a discharge rate of 4C, the battery pack is charged for 15 minutes each time, discharged for 15 minutes, and the single charge and discharge time is 30 minutes. A first type battery pack can maintain uninterrupted charging and discharging for at least 180 minutes (3 hours). Two first type battery packs can be used alternately to power power tools for 3 hours without interruption. Similarly, the battery pack can use the lunch break and transition time to cool down, so the two first type battery packs can supply power for at least 3 hours in the morning, and after the battery packs cool down during the lunch break, they can also supply power for at least 3 hours in the afternoon.

[0192] When the first type of battery pack works continuously at a charging rate of 6C and a discharge rate of 4C, the battery pack is charged for 10 minutes each time, discharged for 15 minutes, and the single charge and discharge time is 25 minutes. When two first type battery packs are used alternately, the charged spare battery pack is installed on the power tool after the working battery pack is emptied. Therefore, although it only takes 10 minutes to fully charge the spare battery pack, it is necessary to wait for the working battery pack to be emptied (the battery pack can continue to cool down during the waiting time), and the total charging time of the battery pack is the sum of the charging time and the waiting time, which is 15 minutes. Therefore, the sum of the total single charging time and discharge time of the battery pack is 30 minutes. Both battery packs can maintain 6 uninterrupted charge and discharge cycles at a charging rate of 6C and a discharge rate of 4C, which means that they can maintain 180 (3 hours) minutes of uninterrupted power supply. Similarly, the battery packs can use the lunch break and transition time to cool down, so the two first-class battery packs can provide power for at least 3 hours in the morning. After the battery packs cool down during the lunch break, they can also provide power for at least 3 hours in the afternoon.

[0193] The temperature rise characteristics of the battery pack in the present application are determined by the following factors. According to the first aspect, the internal resistance of the single cell in the battery pack itself is relatively small (for example, a maximum of about 2 milliohms). Internal resistance is one of the important factors affecting the temperature rise characteristics of the battery pack. The internal resistance of the single cell is less than 2 milliohms, and the number of single cells in the battery pack is not more than 15. Therefore, the internal resistance of the entire battery pack is no more than 30 milliohms. The internal resistance of traditional 18650 cells is typically 15 milliohms, and the internal resistance of the battery pack after assembly is even greater. Since the internal resistance of the single cell in the present application is relatively small, the temperature rise of the single cell is relatively low, and the temperature rise of the entire battery pack after assembly is also relatively low.

[0194] The single cells in the battery pack provided by the present application and the single cells in the traditional lithium battery system 18650 type battery pack with the same capacity were placed at room temperature for charge and discharge temperature rise test. When the test was conducted, the temperature rise of the surface temperature of the single cells in the battery pack provided by the present application and the single cells in the traditional 18650 type battery pack were compared at the same charge rate and discharge rate. The comparison results are shown in Table 1 below:

[0195] As can be seen from Table 1 above, the traditional lithium battery system 18650 type single cell can only support charging at a maximum charging rate of 3C, and cannot support a higher charging rate. If the lithium battery system 18650 type single cell is charged at a charging rate greater than 3C, not only will the capacity and life of the single cell decay rapidly, but in serious cases, there will be safety hazards. This is because when charging at a charging rate exceeding the single cell can withstand, the positive electrode material of the battery will be charged to a very high voltage, thereby releasing excessive lithium ions, and the positive electrode material in a lithium-poor state will decompose and release heat. When the positive electrode potential rises to the electrolyte oxidation decomposition potential, the electrolyte will oxidize and decompose on the positive electrode surface, releasing a large amount of gas and heat. This series of irreversible reactions will not only cause the battery capacity and life to decay, but in serious cases, it may also cause the internal pressure and temperature of the battery to rise sharply, causing the battery to swell and rupture, causing fire and explosion. The single cells in the battery pack provided by the present application can support a charging rate greater than 3C, and when the single cells are charged at a charging rate greater than 3C at room temperature, the temperature rise is also low. When the single cells are charged at a charging rate of 12C at room temperature, the temperature rise is only 17°C. The charging protection temperature of the single cells in the battery pack of the present application is 60°C, so even when the single cells are charged at a charging rate of 12C, the surface temperature of the single cells is still within the normal operating temperature range. Therefore, the battery pack of the present application can be used in application scenarios with high-rate charging.

[0196] Moreover, at the same discharge rate, the surface temperature rise of the traditional lithium battery system 18650 type single cell is greater than the surface temperature rise of the single cell in the battery pack provided in this application. Although the lithium battery system 18650 type single cell can also support a discharge rate greater than 10C, when the discharge rate reaches 10C, the temperature rise of the battery reaches 45°C, that is, under normal temperature conditions (25°C), the surface temperature of the single cell can reach 70°C after discharging at a rate of 10C. When the single cell is discharged at a discharge rate of 12C, the temperature rise reaches 53°C, that is, the surface temperature of the single cell can reach 78°C after the discharge. The normal operating temperature of the 18650 type single cell during discharge is up to 70°C. Therefore, when the single cell is discharged at a rate greater than 10C, the surface temperature of the single cell has exceeded the maximum operating temperature of the single cell during normal discharge. This results in that after the discharge of the single cell, due to the large temperature rise, it is necessary to wait for the temperature of the single cell to cool down to the normal operating temperature range before charging can be started, otherwise it will cause the life of the single cell to decay. The single cell in the battery pack provided by the present application has a temperature rise of 28°C when discharged at a rate of 10C under normal temperature conditions (25°C), that is, the temperature of the single cell after the discharge is 53°C, and a temperature rise of 35°C when discharged at 12C under normal temperature conditions, that is, the temperature is 60°C after the discharge is completed. The normal operating temperature of the single cell of the present application during discharge is up to 70°C, and the temperature of the battery pack is within the normal operating temperature range at a discharge rate of 10C to 12C for the single cell. Therefore, at a discharge rate of 10C to 12C, the temperature of the battery pack composed of this type of cell is also within the normal operating temperature range.

[0197] Secondly, the single cell structure in the present application is designed as a sheet-shaped rectangular cell. The sheet-shaped design can increase the heat dissipation area of ​​the single cell and prevent the internal temperature of the single cell from rising during the charging and discharging process. Figure 5B and Figure 5D As shown, the adjacent single cells in the battery pack are stacked, and the interval Δh between adjacent single cells 231 is greater than or equal to one twelfth of the thickness H of the single cell. By reserving air gaps between adjacent single cells, heat dissipation can be assisted. In the present application, the intervals between adjacent single cells 231 (331) and the cell thickness in the first and second battery packs satisfy the above relationship. In addition, since the charging device has a cooling fan, when charging, the cooling fan of the charging device is started, which can drive the airflow to flow in the air gaps between the single cells to dissipate heat on the surface of the single cells.

[0198] On the third aspect, a thermal management device is also provided in the battery pack, which can adjust the temperature of the battery pack so that the battery pack can work normally even when the ambient temperature is high or low. For example, the thermal management device may include a heating device and / or a heat dissipation device. The heating device can heat the battery pack when the ambient temperature is low to prevent the battery pack from being unable to start charging or discharging due to the battery pack being too low in temperature, so that the battery pack can start charging or discharging immediately even in cold weather. The heat dissipation device can avoid the problem of overheating of the battery pack to a certain extent, so that the battery pack can start charging and discharging even in a high temperature environment.

[0199] It can be seen that the battery pack of the embodiment of the present application can overcome the disadvantage of the high current charging and discharging in the traditional technology that causes the battery pack temperature to rise. The temperature change range of the battery pack after high current charging and high current discharging is small, so that the battery pack can be discharged directly without waiting for cooling after being fully charged, and the battery pack can be charged directly after the discharge is completed without waiting for cooling, so that the waiting time of the power tool is short, which can further improve the working efficiency of the power tool. In addition, since the battery pack has a short charging time, a limited number of battery packs can be used to charge in turn to power the power tool system, thereby reducing the use cost of the power tool system.

[0200] The following is a detailed introduction to the configuration of the battery pack in each usage scenario based on the typical usage scenarios of commercial garden tools.

[0201] There are two typical usage scenarios for commercial gardening tools. The first typical usage scenario is that 1-2 workers form a team and work outside for a day to trim the gardens of 10-20 families, or provide services for municipal or commercial real estate gardens. After the team completes the garden trimming work in one garden, the entire team moves to another garden to continue working. Garden trimming work usually includes mowing, weeding, pruning, blowing grass, etc. Correspondingly, if Fig.16 As shown, the electric tools required for the electric tool system include a wheeled or backpack electric tool 200 and a handheld electric tool 300, wherein the wheeled or backpack electric tool 200 includes a push mower 201, and the handheld electric tool 300 includes a mower 301, a pruner 302, and a hair dryer 303. Depending on the type of electric tool, the type of battery pack in the battery pack system 100 that powers it may also be different, for example, the battery pack system 100 is composed of the first type of battery pack 101, or the battery pack system 100 is composed of the first type of battery pack 101 and the second type of battery pack 102, or the battery pack system 100 is composed of the second type of battery pack 102. When the battery pack on the electric tool is exhausted, the battery pack can be charged by a charging cabinet 700 or an electric car to ensure that the electric tool system has a continuous supply of energy.

[0202] For garden maintenance work, mowing the lawn usually takes the longest time. For a 1,000 square meter garden, the average time for mowing the lawn is 20-30 minutes, and the total time for other work is about the same as mowing the lawn. Therefore, every time Worker A arrives at a garden, he will immediately start mowing the lawn with a hand-pushed lawn mower. While Worker A is mowing the lawn, Worker B will complete other types of work in sequence, such as mowing the lawn, pruning the branches, and blowing the grass. Workers A and B will complete all the work at almost the same time.

[0203] For the common usage scenarios of the first type of commercial garden tools, a variety of methods can be used to configure battery packs for the electric tools required in this usage scenario, so that the energy of the battery pack can support multiple electric tools to work uninterruptedly. The following are several typical battery pack configuration methods:

[0204] In the first way, the battery pack system can be configured by the first type of battery pack. In this example, the capacity of the first type of battery pack can be 11Ah, the continuous charging rate of the first type of battery pack can reach 6C, and the continuous discharge rate can also reach 4C, so that the charging speed of the first type of battery pack is greater than or equal to the discharge speed. Since the hand-push lawn mower has the longest working time, in order not to interrupt the mowing work, a first type of battery pack can be configured separately for the hand-push lawn mower to power it, and the first type of battery pack is installed on the hand-push lawn mower. Since the work of the lawn mower, pruning machine and hair dryer is completed in sequence, a common first type of battery pack can be configured for the lawn mower, pruning machine and hair dryer. The first type of battery pack can be a backpack battery pack that can support the lawn mower, pruning machine and hair dryer to complete the pruning, mowing and blowing of a garden together. Typically, when worker A is mowing with a hand-push lawn mower, worker B is mowing with a lawn mower. After the mowing work is completed, the lawn mower is disconnected from the battery pack, and then the pruning machine is connected to the battery pack, and the pruning machine starts working. After the pruning work is completed, the connection between the pruning machine and the battery pack is released, and the hair dryer is connected to the battery pack, and the hair dryer starts working. If the power tool system is to work uninterruptedly, a backup battery pack can be configured for each of the two power tools working at the same time. When the working battery pack is exhausted, the backup battery pack is used to power the system and charge the working battery pack at the same time. Since the charging speed of the first type of battery pack is greater than the discharging speed, a backup first type battery pack can be configured for each power tool working at the same time. In summary, for the first typical application scenario, four first type battery packs can be configured for the power tool system, two of which are used as working battery packs and two as backup battery packs.

[0205] In the second way, the battery pack system can be configured by a first type of battery pack and a second type of battery pack, and the capacity of the second type of battery pack is less than that of the first type of battery pack. In this example, the capacity of the first type of battery pack can be 11Ah. The capacity of the second type of battery pack is 4Ah. Among them, the charging rate of the second type of battery pack is 12C and the discharge rate is 10C. Due to the large charge and discharge rate, after a charge and discharge cycle, the surface temperature of the battery pack exceeds the charging temperature protection threshold of the battery pack, resulting in the battery pack needing to wait for cooling before it can be used again. Therefore, when the second type of battery pack is used to power the power tool, the number of spare battery packs must be greater than the number of working battery packs. In this example, the first type of battery pack can power a push lawn mower, and the first type of battery pack is installed on the push lawn mower. The second type of battery pack can power handheld power tools such as lawn mowers, pruning machines and hair dryers, and the second type of battery pack can be detachably installed on lawn mowers, pruning machines and hair dryers. In order to improve work efficiency and enable the power tool system to work uninterruptedly, two first-class battery packs can be configured for the push mower, one as a working battery pack and the other as a backup battery pack. When the working battery pack is exhausted, the backup battery pack is installed on the push mower and the working battery pack is charged. Since the charging speed of the first-class battery pack is not less than the discharging speed, the working battery pack is fully charged before the backup battery pack is discharged. Since the temperature rise of the second-class battery pack is high after a charge and discharge cycle, it is necessary to wait for the temperature rise to decrease before continuing to use it. Therefore, for an electric tool, N backup second-class battery packs need to be configured so that N*Tdischarge>Tcharge, where Tdischarge is the discharge time of a single second-class battery pack, and Tcharge is the sum of the waiting time and charging time of a single second-class battery pack after a charge and discharge cycle. When the charging rate of the second type battery pack is 12C and the discharge rate is 10C, at least two spare second type battery packs are required to support the discharge of the power tool, so that after the two battery packs are discharged, the surface temperature of the first discharged battery pack can be reduced to normal temperature, so that the power tool can work uninterruptedly. For example, for a 2KW power power tool, three second type battery packs are required, one of which is used as a working battery pack and two are used as spare battery packs. When the working battery pack is exhausted, wait for the working battery pack to cool down and install the No. 1 spare battery pack on the power tool. When the No. 1 spare battery pack is exhausted, charge the No. 1 spare battery pack, and the temperature of the working battery pack is reduced. Install the No. 2 spare battery pack on the power tool to power the tool. When the No. 2 spare battery pack is powered, charge the working battery pack. When the No. 2 spare battery pack is exhausted, the working battery pack is fully charged and can be put into use again. The three battery packs can support the uninterrupted operation of the power tool by charging and discharging in turn.Furthermore, in order to comply with the usage habits of traditional fuel tools, a second-class battery pack can be pre-installed for each handheld power tool in the power tool system to avoid having to replace the battery pack every time the power tool is replaced, thereby reducing the switching frequency of the battery pack. In this example, for the lawn mower, pruner and hair dryer, a second-class battery pack can be pre-installed respectively, and then two spare battery packs can be configured, so that the lawn mower, pruner and hair dryer can work uninterruptedly. As another example, when configuring the second-class battery pack for the handheld power tool, if the working time of each handheld power tool in a garden is not long, a second-class battery pack can be configured for each handheld power tool.

[0206] In the third way, the battery pack system can be configured entirely by the second type of battery pack. That is, a plurality of second type battery packs can be equipped for a push lawn mower, a grass trimmer, a pruner and a hair dryer, and the plurality of second type battery packs take turns to power the power tool system so that the power tool system can work uninterruptedly. Similarly, in order to conform to the usage habits of traditional fuel tools, a second type battery pack can be pre-installed for each handheld power tool in the power tool system to avoid having to replace the battery pack every time the power tool is replaced, thereby reducing the switching frequency of the battery pack. In this example, a second type battery pack can be pre-installed for the grass trimmer, the pruner and the hair dryer, respectively. When the garden team is working, since the work team includes two people and the two people work at the same time, there are two power tools working at the same time. In order to achieve uninterrupted operation of both power tools, in addition to the working battery pack installed on the power tool, two spare second type battery packs can also be configured for the two power tools working at the same time.

[0207] The second typical application scenario of commercial garden power tools is that a team of 1-2 people works outside for a day to prune the gardens of 10-20 families. The difference between the second typical use scenario and the first typical use scenario is that the type of power tool is not exactly the same. Specifically, Fig.17 and Fig.18 As shown, in the second typical usage scenario, mowing is done by the smart mower 202 or the riding mower 203, the push mower 201 is repaired, and other work is done by the mower 301, the pruner 302 and the blower 303, that is, the electric tool system includes the smart mower 202, the push mower 201, the mower 301, the pruner 302 and the blower 303, or the electric tool system includes the riding mower 203, the push mower 201, the mower 301, the pruner 302 and the blower 303. The work team may include one person or two people.

[0208] like Fig.17As shown, when the electric tool system includes the smart lawn mower 202, the work team may include one person. When the smart lawn mower 202 is mowing, worker A uses the push lawn mower 201 to repair it. After the repair is completed, worker A uses the mower 301, the pruning machine 302 and the blower 303 to perform other work. Alternatively, the work team may include two people. When the smart lawn mower 202 is mowing, worker A uses the push lawn mower 201 to repair it, while worker B uses the mower 301, the pruning machine 302 and the blower 303 to perform other work. After the repair is completed, worker A can assist worker B in his work.

[0209] like Fig.18 As shown, when the electric tool system includes a riding lawn mower 203, the work team may include one person. In this case, the lawn of the garden has been repaired by another gardening company using the riding lawn mower 203. The current gardening company only needs to perform repairs and other non-mowing work, that is, worker A uses the push lawn mower 201 to perform repairs. After the repairs are completed, the worker A uses the lawn mower 301, the pruning machine 302 and the hair dryer 303 to perform other work. Or, Fig.15 As shown, when the power tool system includes a riding lawn mower 203, the work team can also include two people. In this case, the lawn of the garden also needs to be repaired by the current gardening company, that is, worker A uses the riding lawn mower 203 to mow the grass, and worker B uses the push lawn mower 201 to repair it. After the repair is completed, the lawn mower 301, the pruning machine 302 and the hair dryer 303 are used to perform other work. After the mowing work is completed, worker A can assist worker B in other work.

[0210] For the second typical application scenario, the battery pack can be configured in the following ways:

[0211] When the power tool system includes a smart lawn mower and the work team includes 1 person, the battery pack system can be configured by the first type of battery pack. Since there are two power tools working at the same time, that is, the smart lawn mower and the work of worker A, a first type of battery pack can be configured for the smart lawn mower, and the first type of battery pack is installed on the smart lawn mower, and another first type of battery pack is configured for the work of worker A. Typically, worker A installs the first type of battery pack on a push lawn mower. After the repair of the push lawn mower is completed, the connection between the first type of battery pack and the push lawn mower is released, and then the first type of battery pack is installed on the back frame. Worker A carries the first type of battery pack and connects the lawn mower to the first type of battery pack to start the grass cutting work. After the grass cutting work is completed, the connection between the lawn mower and the first type of battery pack is released, and then the pruning machine is connected to the first type of battery pack, and the pruning machine starts working. After the pruning work is completed, the connection between the pruning machine and the first type of battery pack is released, and the hair dryer is connected to the first type of battery pack, and the hair dryer starts working. In order to achieve uninterrupted power supply for the power tool system, it is also necessary to configure a backup battery pack for the power system. Since the charging speed of the first type of battery pack is greater than the discharging speed, a backup first type of battery pack can be configured for each of the power tools working at the same time. When the working battery pack is exhausted, the backup battery pack is used to power the power tool system and charge the working battery pack at the same time. Before or when the backup battery pack is exhausted, the working battery pack is fully charged and can be put into use. Therefore, by configuring four first type of battery packs for the power tool system in this example, the power tool system can be operated uninterruptedly.

[0212] When the power tool system includes a smart lawn mower and the work team includes 1 person, the battery pack system can also be configured by a first type battery pack and a second type battery pack. Among them, the first type battery pack is used to power the smart lawn mower and the hand-push lawn mower, and the second type battery pack is used to power handheld power tools, such as lawn mowers, pruning machines and hair dryers. Similarly, in order to conform to the usage habits of traditional fuel tools, a second type battery pack can be installed in advance for the lawn mower, pruning machine and hair dryer respectively. When working in a garden, the smart lawn mower works non-stop, and the hand-push lawn mower can work intermittently as a supplement. Therefore, two first type battery packs can be configured for the smart lawn mower, one as a working battery pack and the other as a backup battery pack, so that the smart lawn mower can work uninterruptedly. A first type battery pack is configured for the hand-push lawn mower. When the battery pack on the hand-push lawn mower is exhausted, the battery pack is charged, and other handheld tools are used to perform other work while charging. At the same time, since a second-class battery pack is pre-installed on each handheld tool, and workers only use one handheld tool at a time when working, two shared spare second-class battery packs can be configured for multiple handheld tools. In summary, three first-class battery packs and five second-class battery packs can be configured for the system. Typically, when the smart lawn mower is working, worker A uses a hand-push lawn mower to repair it. When the battery pack on the hand-push lawn mower is exhausted, the battery pack is charged. During charging, worker A installs the second-class battery pack on the pruning machine and performs pruning. After the pruning work is completed, the second-class battery pack is installed on the lawn mower to perform mowing. When the second-class battery pack is exhausted, the second-class battery pack is charged, and the spare second-class battery pack is installed on the lawn mower to continue working. When the spare second-class battery pack is exhausted, worker A can install the charged first-class battery pack on the lawn mower and continue to use the hand-push lawn mower to mow. As another example, when configuring the second type of battery pack for handheld power tools, if the working time of each handheld power tool in a garden is not long, a second type of battery pack can be configured for each handheld power tool.

[0213] When the power tool system includes a smart lawn mower and the work team includes 2 people, the battery pack system can be configured by the first type of battery pack. At the same time, there are three power tools working at the same time. The smart lawn mower automatically mows the lawn, worker A uses a push lawn mower to repair, and worker B uses handheld tools to do other work, such as using a lawn mower to mow the lawn, or using a pruning machine to prune the branches, or using a hair dryer to blow the air. Then, a first type of battery pack can be equipped for the smart lawn mower, worker A and worker B respectively, among which workers A and workers B can use backpack battery packs. In order to achieve uninterrupted power supply for the power tool system, three backup battery packs are also needed for the system. When the working battery pack is exhausted, the backup battery pack is used to power the system and charge the working battery pack at the same time. Therefore, six first type battery packs can be equipped for the power tool system.

[0214] When the power tool system includes a smart lawn mower and the work team includes 2 people, the battery pack system can be configured by a first type battery pack and a second type battery pack. Among them, the first type battery pack is used to power the smart lawn mower and the hand-push lawn mower, and the second type battery pack is used to power handheld power tools, such as lawn mowers, pruning machines and hair dryers. Similarly, in order to conform to the usage habits of traditional fuel tools, a second type battery pack can be installed in advance for the lawn mower, pruning machine and hair dryer. When the smart lawn mower mows automatically, worker A uses a hand-push lawn mower to repair, and worker B uses handheld tools to do other work. Then a group of first-type battery packs can be configured for the smart lawn mower to enable it to work uninterruptedly, another group of first-type battery packs can be configured for the hand-push lawn mower to enable it to work uninterruptedly, and two spare second-type battery packs can be configured for the pruning machine, lawn mower and hair dryer to enable it to work uninterruptedly. In this example, the battery pack system may include four first-type battery packs and five second-type battery packs, of which two first-type battery packs and one second-type battery pack are grouped as working battery packs.

[0215] like Fig.18As shown, when the power tool system includes a riding lawn mower and the work team includes 1 person, the battery pack system can be configured by the second type of battery pack. In this work system, lawn mowing is completed by other garden companies using riding lawn mowers, and the current garden company only needs to perform lawn repair and other non-mowing work. Similarly, in order to comply with the usage habits of traditional fuel tools, a second type of battery pack can be installed in advance for each lawn mower, pruning machine and hair dryer. Since the work team consists of 1 person, only one power tool is working at the same time. Typically, worker A first installs a second type of battery pack on a push lawn mower, uses the push lawn mower to perform repair work, charges the battery pack after the battery pack is exhausted, and installs a spare second type of battery pack on the push lawn mower. Preferably, the number of spare second type battery packs can be two. The power tool system is powered by alternating cycles of multiple second type battery packs to complete a family's garden trimming work.

[0216] When the power tool system includes a riding lawn mower and the work team includes 1 person, the battery pack system can be configured by a first type of battery pack and a second type of battery pack. Among them, the first type of battery pack is used to power a riding lawn mower and a push lawn mower, and the second type of battery pack is used to power a handheld power tool, such as a lawn mower, a pruning machine, and a hair dryer. Similarly, a second type of battery pack can be installed in advance for each of the lawn mower, the pruning machine, and the hair dryer. Since the work team consists of 1 person and only one type of power tool is working at the same time, the number of the first type of battery pack in this example can be one, and the number of the second type of battery pack can be five. Typically, worker A can first install the first type of battery pack on the lawn mower and use the lawn mower to perform repair work. After the battery pack on the lawn mower is exhausted, the battery pack is charged, and then worker A starts pruning with the pruning machine. When the second type of battery pack on the pruning machine is exhausted, two spare second type battery packs can be used to power the pruning machine in turn to complete the pruning work. Before or after the pruning is finished, the first type of battery pack is fully charged, and the worker A can install the first type of battery pack on the lawn mower to perform repair work. In this way, by alternately using the lawn mower and other handheld tools, the electric tool system can work uninterruptedly.

[0217] When the power tool system includes a riding lawn mower and the work team consists of 2 people, the battery pack system can be configured with a first type battery pack and a second type battery pack. Among them, the first type battery pack is used to power the riding lawn mower and the push lawn mower, and the second type battery pack is used to power handheld power tools, such as lawn mowers, pruning machines and hair dryers. Similarly, a second type battery pack can be installed in advance for each lawn mower, pruning machine and hair dryer. Worker A uses a riding lawn mower to mow the grass, and worker B uses a push lawn mower to repair it. After the work of worker A is finished, he can assist the work of worker B. In this working system, a set of first type battery packs can be configured for the riding lawn mower and the push lawn mower, and a set of spare second type battery packs can be equipped for the lawn mower, pruning machine and hair dryer. When worker A uses a riding lawn mower to mow the grass, worker B can use a push lawn mower to repair it. After the repair is completed, the lawn mower, pruning machine and hair dryer are used for other work. In order to achieve uninterrupted work, the system requires three first type battery packs and two second type battery packs. Two of the first-class battery packs are used to power a riding lawn mower, one as a working battery pack and the other as a spare battery pack. When worker A uses the riding lawn mower to mow the lawn, worker B uses a push lawn mower to do repairs, so the third first-class battery pack is used to power the push lawn mower. When the battery pack on the push lawn mower is exhausted, the battery pack is charged. While charging, worker B can use a pruning machine to prune, and after the second-class battery pack on the pruning machine is exhausted, two spare second-class battery packs are used to power the pruning machine in turn to complete the pruning work. Similarly, after the pruning work is completed, mowing is performed. When the spare second-class battery pack is exhausted, worker B can install the charged first-class battery pack on the lawn mower and continue to use the push lawn mower to mow the lawn. In this way, by alternating the use of the lawn mower and other handheld tools, the power tool system can work uninterruptedly.

[0218] Fig.19A An exploded view of the battery pack is shown. Specifically, Fig.19A and Fig.19B The temperature control of the battery pack is highlighted. There are a total of 8 temperature sensors. Five sensors are used to detect the temperature of the positive and negative electrodes of the battery and are installed on the circuit board connected to the positive and negative electrodes of the battery. The detected temperature value is used to adjust the charging current. One sensor is used to detect the temperature of the MOS and prevent the MOS from overheating. One sensor is used to detect the temperature of the current sensor and is further used to correct the inaccurate detection of the current sensor as the temperature increases. One sensor is used to detect the temperature of the charging electrode of the battery pack to determine the reliability of the connection between the battery pack and the charger (not shown in the figure). Fig.19C Shown are 65Mn steel plates 1810 that are added to the corners of the shell to strengthen the shell in the event that the shell is dropped. Fig.19DThe honeycomb air inlet 1820 is highlighted, and a filter (not shown) is placed near the honeycomb air inlet 1820 to prevent contaminants from entering the housing.

[0219] It should be noted that, although the above embodiment is described with a battery pack having a nominal voltage of 60V as an example, when the nominal voltage of the battery pack is other voltage values, the relationship between the charging rate and the discharging rate of the battery pack can still enable the battery pack to meet the above-mentioned state of uninterrupted cyclic use, so as to reduce the use cost of the battery pack. For example, when the voltage of the battery pack is 20V, the output current of the battery pack is not less than 60A, so that the battery pack can meet the high power requirements of the power tool. If the capacity of the battery pack is 11Ah and the discharge current is 60A, the discharge rate of the battery pack is about 6C. By configuring the output current of the mobile charging device, the charging rate of the battery pack can be made not less than 6C, and when the charging rate is not less than 6C, the temperature of the battery pack during charging is less than the temperature protection threshold of the battery pack, so that the battery pack can be discharged immediately after the charging is completed, and charged immediately after the discharging is completed, so as to realize the uninterrupted use of the battery pack.

[0220] like Fig. 20 As shown, possible scenarios for charging the battery pack for a working day. A typical working scenario for outdoor commercial garden tools is that a team equipped with mowers, pruning machines, blowers and other tools works outdoors for a day to mow the gardens of 10-20 families. In each garden, worker A will mow the grass with a mower. While worker A is mowing the grass, worker B will do other types of work in turn. For example, worker B will mow and then blow the grass. Once the team has finished working in one garden, they go to another garden and repeat the process until they have completed all the work for the day. In order to improve work efficiency to complete as many gardens as possible, the power of outdoor commercial garden tools is usually high. For example, the power of garden blowers is usually 2300W and the power of lawn mowers is usually 2600W. In addition, vehicles can be used to charge mobile charging devices and / or battery packs. Optionally, the battery pack can be charged with an available AC power source. Therefore, when using battery packs instead of gasoline to power outdoor commercial garden tools, there are the following challenges: 1) How to provide electricity for a day.

[0221] If the capacity of the battery pack is large enough, the pack may be too heavy, making the tool difficult to use. If the battery pack is light enough, it may not have enough capacity to last a day. Carrying enough small battery packs may be too costly. 2) How to meet the requirement of electricity being available at any time without waiting.

[0222] Existing power tool battery packs (usually lithium battery packs) have a maximum charge rate of 3C and take 20 minutes to fully charge. The charging time is longer than the discharge time. After fully charging, the temperature rises and the tool cannot be used immediately. Therefore, after the tool uses up one battery pack, it must wait for another battery pack to be used. This causes users to have to wait longer for power, work less time, and reduce work efficiency. 3) How to meet high power requirements.

[0223] Existing power tool battery packs (usually lithium battery packs) have a maximum discharge current of about 20A. The discharge power it can provide is generally between 400W and 800W. To achieve a power of 2000W, the number of cells needs to be increased, which will not only increase the weight of the battery pack, but also increase the complexity of the battery management system. 4) How to meet the requirements of low life cycle costs.

[0224] Existing power tool battery packs (usually lithium battery packs) have a cycle life of 300 to 1,000 cycles. Considering that the number of battery packs equipped by an outdoor team in a day is not too large, each battery pack may need to be recycled 8 to 10 times a day, and the battery pack life will end within 1 to 3 months, resulting in high battery pack usage costs.

[0225] For challenge 1), the battery pack described in this paper takes into account the weight of the battery pack and the power consumption of one day, and uses a mobile charging device and multiple relatively light battery packs. The battery pack powers the power tool to ensure its operability. The mobile charging device stores one day's power, and when the battery pack is out of power, it can follow the user to each work site at any time to charge the battery pack.

[0226] like Fig. 20 As shown, the battery pack includes a first type of battery pack 308 (e.g., a backpack battery pack) and a second type of battery pack 306 (e.g., a handheld battery pack), which power different types of tools and can be charged by the same mobile charging device 304. Optionally, the second type of battery back has less energy and lighter weight than the first type of battery pack. Therefore, the second type of battery pack is more suitable for handheld power tools, while the first type of battery pack is more suitable for wheeled power tools or backpack power tools. When AC power is available, the battery pack can also be charged by a common charger. Optionally, the battery pack can be charged by an electric vehicle (EV). The mobile charging device 304 charges itself using an EV charger or AC power. Commercial electric garden tools and others can be provided with the same tool port. The first or second type of battery packs all have the same charging and discharging ports. All tools can be used with the first or second type of battery pack.

[0227] The mobile charging device is composed of a charging component and an energy storage component. The charging component is configured to be connected to a battery pack (e.g., a first battery pack and a second battery pack). The energy storage component is configured to store enough electrical energy for a plurality of jobs. Each of the plurality of jobs may be located in a different geographic location, and the plurality of jobs is the amount of work that a worker is expected to complete in a workday (e.g., from sunrise to sunset, from sunrise to a time determined by a local noise ordinance, or any suitable workday).

[0228] In one embodiment, a mobile charging device includes a charging component capable of connecting to a first battery pack and a second battery pack, and an energy storage component configured to store sufficient electrical energy for multiple operations, wherein the charging component and the energy storage component are independent and separate within the mobile charging device.

[0229] The charging component and the energy storage component are independent and separate within the mobile charging device. The charging component and the energy storage component can be connected together (e.g., locked together) within the mobile charging device. In some examples, the mobile charging device can have 5kWh of energy, a maximum charging power of up to 1800W, a maximum discharge power of up to 6000W, a full charge time of 3.3 hours, and a discharge rate of 1.2C. In addition, the internal resistance of the battery cell of the mobile charging device can be greater than the internal resistance of the battery cell contained in the first and / or second battery pack.

[0230] For challenge 2), the charging speed of the battery pack is faster than that of the lithium battery pack so that the charging speed is close to the discharge speed of the battery pack. The charging rate of existing lithium battery packs is usually slower than the discharge rate.

[0231] Based on this feature, the battery pack described in this article is divided into two parts: battery pack A and battery pack B. Each part includes one, two or three battery packs. When battery pack A supplies power to the tool, battery pack B is charged by a mobile charging device. The charging speed of battery pack B in the mobile charging device is basically the same as the discharge speed of battery pack A in the tool. In this way, once the power in battery pack A is exhausted, battery pack B is fully charged. Then, battery pack B supplies power to the tool, and battery pack A is charged by the mobile charging device. This cycle ensures that the tool can continue to be powered without waiting.

[0232] In addition, the battery pack can be charged in about 5 minutes using a mobile charging unit. Thus, the battery pack can be fully charged on the way to another garden.

[0233] For challenge 3), the battery pack can provide high power by utilizing the large discharge rate of the battery pack. The ability to discharge at a high rate allows the battery pack to discharge high current, thereby providing high power.

[0234] For Challenge 4), the battery pack has a long cycle life of up to 5,000 charge and discharge cycles. A longer cycle life can reduce operating costs. In a preferred embodiment, the life cycle of the battery pack is greater than 2,500 cycles at an ambient temperature of about 0°C to about 45°C (e.g., about 5°C to about 45°C, about 0°C to about 40°C, about 5°C to about 40°C, or about 10°C to about 35°C). In some examples, when the battery pack is charged at a charge rate of 5C and discharged at a rate of 5C, the capacity retention rate of the battery pack after 2,500 cycles can reach at least 75%.

[0235] For typical application scenarios and in order to achieve continuous operation of the power tool system, each battery pack needs to be repeatedly charged and discharged many times. During mowing a garden, each battery pack requires one or two charge and discharge cycles (for example, the battery pack is charged and then discharged using a power tool), and a work team needs to mow the gardens of 10 to 20 families in one day of outdoor work. Therefore, the number of charge and discharge times for each battery pack in the battery pack system is as high as 10 to 20 times a day. If the service life of the battery pack is relatively short, it will lead to the need to frequently update the battery pack, resulting in higher use costs.

[0236] The common ternary lithium battery system 18650 battery pack on the market currently has a charging rate of less than 3C, usually 0.5C to 1C, and a slow charging speed. If the charging current is forcibly increased and the charging rate is increased, the life of the battery pack will be shortened. If the 18650 battery pack is applied to the typical application scenario of the aforementioned commercial garden tools, when the battery pack is charged and discharged at a charging rate of 0.5C, the number of charge and discharge cycles of the battery pack can reach 1500 times, and the capacity retention rate after 1500 cycles of charge and discharge is 80% of the rated capacity of the battery pack. The capacity retention rate is the ratio between the actual capacity of the battery pack and the rated capacity of the battery pack after the battery pack is recharged. As the number of times the battery pack is charged increases, the actual capacity of the battery pack will decrease, and the smaller the decrease rate (that is, the greater the capacity retention rate of the battery), the better the capacity retention performance of the battery. Due to the small charging rate and slow charging speed of the traditional 18650 battery pack, the charging waiting time of the power tool is long. If you want to make the power tool work uninterruptedly, you need to prepare more spare battery packs, which increases the cost of use. If you increase the charge and discharge rate of the battery pack, and make the battery pack charge and discharge cyclically at a 3C charge rate, the life of the battery pack will be reduced to about 300 times, and the battery pack needs to be replaced frequently, which will also increase the cost of use.

[0237] Another common lithium iron phosphate system 21700 battery pack has a charging rate of less than 1C. When the battery pack is charged and discharged at a charging rate of 1C, the number of charge and discharge cycles of the battery pack is no more than 1000 times, and the capacity retention rate after 1000 cycles of charge and discharge is 70% of the rated capacity of the battery pack. Therefore, the common lithium iron phosphate system battery pack has a low charging rate and a slow charging speed, which cannot meet the fast charging requirements of commercial garden power tools. If the charging rate of the battery pack is increased, the service life of the battery pack will be reduced, and the battery pack needs to be replaced frequently during use, resulting in an increase in the cost of using the battery pack.

[0238] Therefore, in the aforementioned application scenarios, the traditional ternary lithium battery system 18650 battery pack and lithium iron phosphate system 21700 battery pack are difficult to meet the needs of commercial garden power tools.

[0239] When the battery pack is continuously charged and discharged at a charge rate of 3C or more and a discharge rate of 3C or more, the maximum number of charge and discharge cycles of the battery pack is not less than 2000 times, and after 2000 cycles of charge and discharge, the capacity retention rate of the battery pack is not less than 80% of the rated capacity of the battery pack. It should be noted that when the battery pack is undergoing a life test, it is discharged after the temperature drops to room temperature after charging, and it is charged after the temperature drops to room temperature after discharging.

[0240] Optionally, when the battery pack is continuously charged and discharged at a charge rate of 3C and a discharge rate of 10C, the number of charge and discharge cycles of the battery pack can reach 2500 times or more, and the capacity retention rate of the battery pack after 2500 charge and discharge cycles is not less than 75% of the rated capacity of the battery pack.

[0241] Optionally, when the battery pack is continuously charged and discharged at a charge rate of 3C and a discharge rate of 3C, the number of charge and discharge cycles of the battery pack can reach or exceed 5000 times, and after 5000 charge and discharge cycles, the capacity retention rate of the battery pack is not less than 80% of the rated capacity of the battery pack.

[0242] Optionally, when the battery pack is continuously charged and discharged at a charge rate of 4C and a discharge rate of 4C, the service life of the battery pack can reach or exceed 5000 times, and after 5000 charge and discharge cycles, the capacity retention rate of the battery pack is not less than 80% of the rated capacity of the battery pack.

[0243] Optionally, when the battery pack is continuously charged and discharged at a charge rate of 5C and a discharge rate of 5C, the service life of the battery pack can reach or exceed 5000 times, and after 5000 charge and discharge cycles, the capacity retention rate of the battery pack is not less than 80% of the rated capacity of the battery pack.

[0244] Optionally, when the battery pack is continuously charged and discharged at a charge rate of 5C and a discharge rate of 10C, the service life of the battery pack can reach or exceed 5000 times, and after 5000 charge and discharge cycles, the capacity retention rate of the battery pack is not less than 80% of the rated capacity of the battery pack.

[0245] Optionally, when the battery pack is continuously charged and discharged at a charge rate of 10C and a discharge rate of 10C, the service life of the battery pack can reach or exceed 5000 times, and after 5000 charge and discharge cycles, the capacity retention rate of the battery pack is not less than 80% of the rated capacity of the battery pack.

[0246] Optionally, when the battery pack is continuously charged and discharged at a charge rate of 10C and a discharge rate of 15C, the service life of the battery pack can reach or exceed 5000 times, and after 5000 charge and discharge cycles, the capacity retention rate of the battery pack is not less than 80% of the rated capacity of the battery pack.

[0247] It should be noted that during the service life test, after each charge, the battery pack will wait for the temperature to drop before discharging to prevent the battery pack temperature from reaching the discharge protection temperature value during discharge. After each discharge, the battery pack will wait for the battery pack temperature to drop before charging to prevent the battery pack temperature from reaching the charging temperature protection value during charging.

[0248] As a specific example, when the first type of battery pack is charged and discharged at a charge rate of not less than 6C and a discharge rate of not less than 4C, the number of charge and discharge cycles of the battery pack is greater than or equal to 2000 times, and when the charge and discharge cycles reach 2000 times, the capacity retention rate of the battery pack is not less than 80% of the rated capacity. Specifically, when the first type of battery pack is charged and discharged at a charge rate of 6C and a discharge rate of 4C, the number of charge and discharge cycles of the battery pack is not less than 5000 times.

[0249] When the second type battery pack is continuously charged and discharged at a charge rate of not less than 12C and a discharge rate of not less than 10C, the number of charge and discharge cycles of the battery pack is greater than or equal to 2000 times, and when the charge and discharge cycles reach 2000 times, the capacity retention rate of the battery pack is not less than 80% of the rated capacity. Specifically, when the first type battery pack is charged and discharged at a charge rate of 12C and a discharge rate of 10C, the number of charge and discharge cycles of the battery pack is not less than 5000 times.

[0250] It can be seen that the charging rate of the battery pack provided by the present application is much greater than the charging rate of the common battery packs on the market, and at a large charge and discharge rate, the service life is also much greater than the service life of the common battery packs on the market, and is more suitable for the use of commercial garden power tools. When the battery pack provided by the present application is used to support the uninterrupted operation of the power tool system, frequent replacement of new battery packs can be avoided, thereby reducing the overall working cost of the power tool system.

[0251] In addition, the battery pack provided by the present application not only has a large charging rate and a long life, but also has a good temperature rise performance under the conditions of a large charging rate and a long life. Specifically, when the battery pack is charged and discharged at a charging rate of not less than 3C and a discharge rate of not less than 3C, the number of cycles of the battery pack is not less than 2000 times. After 2000 cycles of charge and discharge, the capacity retention rate of the battery pack is not less than 80% of the rated capacity of the battery pack, and the temperature rise of the battery pack is 3°C during the charging process of the battery pack at a charging rate of 3C, and the temperature rise of the battery pack is 10°C during the discharge process of the battery pack at a discharge rate of 3C.

[0252] As a specific example, when the first type of battery pack is charge and discharge cycled at a charge rate of 6C and a discharge rate of 4C, the number of charge and discharge cycles of the battery pack is greater than or equal to 2000 times. When the charge and discharge cycles reach 2000 times, the capacity retention rate of the battery pack is not less than 80% of the rated capacity, and the charging temperature rise of the battery pack during the charging process is 12°C, and the discharge temperature rise of the battery pack during the discharging process is 15°C.

[0253] As another specific example, when the second type battery pack is charge and discharge cycled at a charge rate of 12C and a discharge rate of 10C, the number of charge and discharge cycles of the battery pack is greater than or equal to 2000 times. When the charge and discharge cycles reach 2000 times, the capacity retention rate of the battery pack is not less than 80% of the rated capacity, and the charging temperature rise of the battery pack during the charging process is 33°C, and the discharge temperature rise is not more than 35°C.

[0254] Since the battery pack provided in the present application has a high charging rate, by setting the charging rate and discharge rate of the battery pack, the charging speed of the battery pack can be made equivalent to the discharge speed, or even the charging speed can be greater than the discharge speed. Therefore, when the battery pack is used for commercial garden power tools, the garden team can achieve uninterrupted operation of the power tools by configuring a small number of battery packs.

[0255] To sum up, by rationally configuring the type and quantity of battery packs according to the number of power tools working simultaneously, the garden team can carry a small number of battery packs to continuously power the power tool system, thereby improving the working efficiency of the power tool system. In addition, due to the long service life of the battery pack, the cost of using the battery pack can be reduced, allowing power tools to replace traditional fuel tools.

[0256] In addition, the maximum output power of the battery pack of the present application is not less than 2000W, and the power of the battery pack is not more than 1KWh. Therefore, the battery pack can output high power at a lower power level to support the operation of high-power electric tools.

[0257] Furthermore, the number of single cells in the battery pack does not exceed 15. Specifically, the number of single cells in the battery pack can be 15, and each single cell is connected in series to power the power tool. Therefore, the battery pack provided in this embodiment has an output power of not less than 2000W, a power of the battery pack is not more than 1KWh, and the number of single cells in the battery pack does not exceed 15. By designing the output power of the battery pack, the power of the battery pack and the number of cells, the output power of the battery pack can meet the power requirements of the power tool, and the power design of the battery pack and the number of cells are designed so that the battery life of the battery pack meets the requirements of the power tool, and the weight of the battery pack does not affect the comfort of use.

[0258] The battery pack provided in the present application has an energy density greater than or equal to 100Wh / Kg. Specifically, the energy density of the battery pack can be 130Wh / Kg. Among them, the energy density of the first type of battery pack is greater than or equal to 600Wh, and the energy density of the second type of battery pack is greater than or equal to 216Wh.

[0259] Usually, in order to reduce the number of battery packs that gardeners carry when they go out to work with power tools and ensure the battery life of power tools, the general research direction in the industry is to improve the energy density of battery packs, so that a single battery pack can store as much power as possible without changing its weight, so that the work team can carry a small number of battery packs when going out to work to achieve uninterrupted work of power tools. For example, the energy density of the 18650 type battery pack of the traditional ternary lithium battery system is 180Wh / Kg~240Wh / Kg. The energy density of the 21700 type battery pack of the traditional lithium iron phosphate battery system is greater than or equal to 150Wh / Kg. In order to improve the energy density, various battery manufacturers will start with the cell structure, and increase the cell size by fine-tuning the cell structure to achieve the effect of power expansion. However, as the cell size increases, the cell mass will also increase. Therefore, adjusting the cell structure can only treat the symptoms but not the root cause. The key lies in finding positive and negative electrode materials with high energy density. Research on positive and negative electrode materials has reached a bottleneck stage, so the energy density of the cell is limited.

[0260] In response to the battery life issue of garden power tool systems, the present application provides another research direction, which is to increase the charging rate of the battery pack to increase the charging speed of the battery pack, so that the charging speed of the battery pack is close to the discharging speed. A small number of battery packs can be used to power the power tool to achieve uninterrupted operation of the power tool. For example, two first-class battery packs or three second-class battery packs can be used to achieve uninterrupted power supply for a working power tool, so that the work team can carry a small number of battery packs when going out to work to achieve uninterrupted operation of the power tool, which not only improves the portability of the battery pack system, but also reduces the use cost of the battery pack system.

[0261] Another embodiment of the present application provides a battery pack system, comprising a plurality of battery packs as described above, for alternately powering a power tool system. The power tool system may include one or more commercial gardening power tools. For example, if the power tool system needs to perform a single task that can be completed by one type of power tool, then only one power tool may be configured for the user. For another example, if the power tool system needs to perform a variety of tasks that require the cooperation of multiple power tools to complete, then the battery pack system includes multiple power tools.

[0262] Another embodiment of the present application provides an electric tool system, including at least one garden-type electric tool. Among them, the configuration of the electric tools in the electric tool system is as described above. The garden-type electric tool includes a main body, a motor, a motor output shaft and a working part. The motor is arranged in the main body for providing power. The motor output shaft is connected to the motor for rotating under the drive of the motor. The working part is coupled to the motor output shaft for working under the drive of the motor output shaft. The electric tool system also includes a battery pack system, the battery pack system includes a plurality of the aforementioned battery packs, the battery packs are detachably connected to the electric tool, and are used to replaceably provide electrical energy to the aforementioned electric tool system, so that the aforementioned electric tool system can achieve uninterrupted operation.

[0263] Further, the power tool system includes at least two of garden power tools such as a hair dryer, a lawn mower, a lawn mower, a pruner, and a brush cutter. The output power of the garden power tool is greater than or equal to 1200W. Preferably, the output power of the garden power tool is greater than or equal to 1600W. More preferably, the output power of the garden power tool is greater than or equal to 2000W.

[0264] In the present application, the number of battery packs in the battery pack system can be configured according to the number of electric tools working simultaneously in the garden electric tool system. Preferably, the number of battery packs can be configured to be no less than the number of battery packs required when the electric tool system is working. More preferably, the number of battery packs can be configured to be no less than twice the number of battery packs required when the electric tool system is working. The number of battery packs required when the electric tool system is working can be understood as the maximum number of battery packs that the electric tool system needs to use at the same time when working.

[0265] The battery pack is used to power the power tool system, so that the power tool system can work continuously with a relatively small number of battery packs, thereby reducing the cost of using the battery pack and improving the working efficiency of the power tool. In addition, the garden team can carry the battery pack conveniently when working outside.

[0266] In at least one embodiment, a battery pack includes a housing and at least one battery cell disposed in the housing. The housing is provided with a charge and discharge port so that the battery pack can be electrically and mechanically connected to a power tool to provide power. The battery pack can be provided in a specific manner with reference to the foregoing embodiments, and of course can also be provided in other ways. Each of the at least one battery cell has a capacity of at least 3.6 Ah, a maximum allowable charge rate of at least 5 C, and an internal resistance of at least 3 milliohms.

[0267] In one example, the battery pack includes a plurality of cells, the internal resistance of the plurality of cells is not greater than 45 milliohms, and the capacity of the plurality of cells is not less than 4Ah. In another example, the battery pack includes a plurality of cells, the internal resistance of the plurality of cells is not greater than 13.5 milliohms, and the capacity of all the plurality of cells is not less than 11Ah.

[0268] The multiple cells in the battery pack can be connected in series, in parallel, or in series and in parallel. The multiple cells are connected to each other in at least one of these ways to form the multiple cells. The internal resistance of the multiple cells is less than or equal to the internal resistance of the battery pack. This is because the internal resistance of the battery pack includes not only the internal resistance of the multiple cells, but also the internal resistance of the circuit connecting the multiple cells to the positive terminal and the negative terminal of the battery pack and the internal resistance of the positive terminal and the negative terminal of the battery pack. The capacity of the multiple cells is equal to the capacity of the battery pack.

[0269] In one example, the battery pack includes 15 cells connected in series, each cell having a capacity of not less than 4Ah, an internal resistance of not more than 3 milliohms, and a rated voltage of not less than 4V. The rated voltage of the battery pack is not less than 60V, and the capacity of the battery pack is not less than 4Ah. In another example, the battery pack includes 15 cells connected in series, each cell having a capacity of not less than 10Ah, an internal resistance of not more than 0.9 milliohms, and a rated voltage of not less than 4V. The rated voltage of the battery pack is not less than 60V, and the capacity of the battery pack is not less than 10Ah.

[0270] In one example, the battery pack includes 15 cells connected in series, each cell having a capacity of 4Ah, a maximum allowable charge rate of 10C, and an internal resistance of less than 3 milliohms. Optionally, the internal resistance of each cell is in the range of 1.8 milliohms to 3 milliohms, such as 1.9 milliohms, 2 milliohms, 2.2 milliohms, and 2.6 milliohms. Then the capacity of the battery pack is 4Ah, the maximum allowable charge rate of the battery pack is 10C, and the internal resistance of multiple cells is 27 milliohms to 45 milliohms. Optionally, the rated voltage of each cell is 4V, and the rated voltage of the battery pack is 60V. In another example, the battery pack includes 15 cells connected in series, each cell having a capacity of 11Ah, a maximum allowable charge rate of 10C, and an internal resistance in the range of 0.75 milliohms to 0.85 milliohms. Then the capacity of the battery pack is 11Ah, the maximum allowable charge rate of the battery pack is 10C, and the internal resistance of multiple cells is not greater than 13 milliohms. Optionally, the rated voltage of each battery cell is 4V and the rated voltage of the battery pack is 60V.

[0271] In one example, the battery pack includes 5 cells connected in series, each cell having a capacity of 4Ah, a maximum allowable charge rate of 10C, and an internal resistance in the range of 1.8 milliohms to 3 milliohms. Then the capacity of the battery pack is 4Ah, the maximum allowable charge rate of the battery pack is 10C, and the internal resistance of the multiple cells is 9 milliohms to 15 milliohms. Optionally, the rated voltage of each cell is 4V, and the rated voltage of the battery pack is 20V. In another example, the battery pack includes 5 cells connected in series, each cell having a capacity of 11Ah, a maximum allowable charge rate of 10C, and an internal resistance in the range of 0.75 milliohms to 0.85 milliohms. The capacity of the battery pack is 11Ah, the maximum allowable charge rate of the battery pack is 10C, and the internal resistance of the multiple cells ranges from 3.75 milliohms to 4.25 milliohms. Optionally, the rated voltage of each cell is 4V, and the rated voltage of the battery pack is 20V.

[0272] In at least one example, the maximum allowable charge rate of the battery cell may be 5C, 8C, 10C, or 12C. When the maximum allowable charge rate is within the range of 10C to 12C, the battery pack containing the battery cell can be fully charged in 5 to 6 minutes. The charging speed is so fast that a single charge is as fast as a gasoline engine refueling, so that after replacing a gasoline tool with an electric tool equipped with the battery pack, the user's habit of using the electric tool is the same as that of the gasoline tool, without adding additional waiting time.

[0273] In at least one example, the battery pack includes 6, 8, 10, 12, 16, 20 or 30 cells, etc. The cells can be connected only in series with each other, or they can be connected in series and in parallel. The more cells are connected in series, the higher the voltage of the battery pack, and the more cells are connected in parallel, the greater the capacity of the battery pack. In at least one embodiment, each cell can have a capacity of 3.6Ah, 5Ah, 6Ah, 8Ah, 10Ah, 12Ah or 14Ah.

[0274] In at least one example, the internal resistance of each battery cell has a predetermined corresponding relationship with the capacity. Optionally, the predetermined corresponding relationship is such that as the capacity of each battery cell increases, the internal resistance decreases. Optionally, the capacity of each battery cell is inversely proportional to the internal resistance. Optionally, the product of the capacity (Ah) and the internal resistance (milliohms) of each battery cell ranges from 6 to 12. In one example, the capacity of the battery cell is 4Ah, and the internal resistance of the battery cell ranges from 1.8 milliohms to 2.8 milliohms. In another example, the capacity of the battery cell is 2Ah, and the internal resistance of the battery cell ranges from 3 milliohms to 4 milliohms. In another example, the capacity of the battery cell is 6Ah, and the internal resistance of the battery cell ranges from 1.4 milliohms to 1.7 milliohms. In another example, the capacity of the battery cell is 11Ah, and the internal resistance of the battery cell ranges from 0.75 milliohms to 0.85 milliohms.

[0275] In at least one embodiment, the battery pack includes at least one battery cell. The battery pack has a low temperature rise during high-rate charging and discharging, so that the battery pack will not trigger over-temperature protection due to high temperature after completing high-rate charging and discharging. This allows the battery pack to be used continuously without waiting for the temperature to drop. Over-temperature protection means that the charger or battery pack detects that the temperature of the battery pack is too high during the charging process of the battery pack. In order to prevent the high temperature from affecting the performance or life of the battery pack, the charger stops further charging the battery pack, or in the process of discharging the battery pack, the battery pack or power tool detects that the temperature of the battery pack is too high. In order to prevent the high temperature from affecting the performance or life of the battery pack, the battery pack stops further discharging to the tool. The higher the allowable discharge rate, the higher the power output of the battery pack, and the higher the power available for the power tool used with the battery pack, so the higher the power output of the power tool, the higher the efficiency. Similarly, the higher the charge rate allowed by the battery pack, the shorter the time required for the battery pack to be fully charged, thereby saving a lot of waiting time for the user. With high power output, short charging waiting time and the ability to work continuously, such battery packs solve the long-standing power anxiety problem in the field of power tools and are easily widely appreciated by users.

[0276] Combine the following Figures 21 to 30 Describe the temperature characteristics of the battery pack at different charge and discharge rates. In at least one embodiment, the battery pack is temperature tested according to the following test conditions, and the temperature change curve during the test is recorded and displayed in Figures 21 to 30 In these figures, the horizontal axis represents time and the vertical axis represents temperature. The solid line is the temperature of the first test point and the dotted line is the temperature of the second test point.

[0277] The test conditions include a test environment temperature of approximately 25°C, such as 25°C ± 3°C, or 20°C ± 3°C, or 30°C ± 3°C. In each of the following tests, the temperature at the test start point can be used to determine which of the above temperature ranges the test environment temperature belongs to. There is no fan cooling the battery pack during charging. Two test points are arranged inside the battery pack, and the battery pack is then charged or discharged at a fixed rate. During the charging process, the charging current, voltage and temperature of the battery pack are monitored. When the charging current is less than or equal to a preset current value, the charging process stops. The temperature rise of the battery pack during the charging process is obtained by comparing the temperature at the beginning of charging with the temperature at the end of charging, and the preset current value is greater than or equal to the current value corresponding to the 1C charging rate. During the discharge process, the voltage and temperature of the battery pack are monitored. When the voltage of the battery pack is less than or equal to the preset voltage value, the discharge process is stopped. The preset voltage value is greater than or equal to 2.5V per battery cell. The temperature rise of the battery pack during the discharge process can be obtained by comparing the temperature at the beginning of discharge with the temperature at the end of discharge.

[0278] In one embodiment, the battery pack includes 15 cells connected in series, each cell having a capacity of 4Ah. The battery pack is charged at a 3C charging rate according to the above test conditions to obtain a data curve of temperature change over time, such as Fig.21 As shown. According to this test curve, it can be seen that during the entire charging process, the temperature of the battery pack increases with time. The temperature change reflected by the solid line shows that the temperature at point A is 17°C at the beginning of the test and the temperature at point B is 28°C at the end of the test. During charging at a 3C charging rate, the temperature rise of the first test point of the battery pack is 11°C. The temperature change reflected by the dotted line indicates that the temperature at point A' is 17°C at the beginning of the test and the temperature at point B' is 27°C at the end of the test. During charging at a 3C charging rate, the temperature rise of the second test point of the battery pack is 10°C.

[0279] In one embodiment, the battery pack includes 15 cells connected in series, and each cell has a capacity of 11Ah. The battery pack is charged at a 3C charging rate according to the above test conditions. The data curve of temperature change over time is as follows: Fig. 22 As shown. According to this test curve, it can be seen that during the entire charging process, the temperature of the battery pack increases with time. The temperature change reflected by the solid line shows that the temperature at point A was 17°C at the beginning of the test, and the temperature at point B was 28°C at the end of the test. The temperature rise of the first test point of the battery pack during the 3C charging rate charging process was 11°C. The temperature change reflected by the dotted line shows that the temperature at point A' was 17°C at the beginning of the test, and the temperature at point B' was 25°C at the end of the test. The temperature rise of the second test point of the battery pack during the 3C charging rate charging process was 8°C.

[0280] According to the temperature test results of the battery pack at the 3C charging rate, the temperature rise of the battery pack at the four test points is 11°C, 10°C, 11°C and 8°C. The lowest temperature rise is 8°C and the highest temperature rise is 11°C. Therefore, the temperature rise range of the battery pack at the 3C charging rate is 8°C to 11°C. Taking into account the ±3°C error in the test, the temperature rise range of the battery pack is 5°C to 14°C. In other words, when charged at a 3C charging rate, the temperature rise of the battery pack does not exceed 14°C.

[0281] According to the temperature test results of the above-mentioned battery pack at a 3C charging rate, when the capacity of the battery cell in the battery pack is 4Ah, the temperature rise at the two test points of the battery pack is 11°C and 10°C respectively. When the capacity of the battery cell in the battery pack is 11Ah, the temperature rise at the two test points is 11°C and 8°C respectively. It can be seen that the temperature rise of the battery pack varies according to the capacity of the battery cell. At a 3C charging rate, the difference is in the range of 0°C to 2°C. Since the difference is small, it can be ignored. The temperature rise of the battery pack with small-capacity batteries is slightly higher than that of the battery pack with large-capacity batteries.

[0282] In one embodiment, the battery pack includes 15 cells connected in series, each cell having a capacity of 4Ah. The battery pack is charged at a 5C charging rate according to the above test conditions to obtain the following Fig.23 The data curve of temperature change over time is shown. According to this test curve, it can be seen that the temperature of the battery pack increases with time during the entire charging process. The temperature change reflected by the solid line shows that the temperature at point A is 18°C ​​at the beginning of the test and the temperature at point B is 33°C at the end of the test. During the charging process of the battery pack at a 5C charging rate, the temperature rise of the first test point is 15°C. The temperature change reflected by the dotted line shows that the temperature of point A' at the beginning of the test is 17°C, and the temperature of point B' at the end of the test is 33°C. During the charging process at a 5C charging rate, the temperature rise of the second test point of the battery pack is 16°C.

[0283] In one embodiment, the battery pack includes 15 cells connected in series, each cell having a capacity of 11 Ah. The battery pack is charged at a 5C charging rate according to the above test conditions to obtain a data curve of temperature change over time, such as Fig.24 As shown. According to this test curve, it can be seen that during the entire charging process, the temperature of the battery pack increases with time. The temperature change reflected by the solid line shows that the temperature at point A is 25°C at the beginning of the test, and the temperature at point B is 38°C at the end of the test. During the charging process of the battery pack at a 5C charging rate, the temperature rise of the first test point is 13°C. The temperature change reflected by the dotted line shows that the temperature of point A' at the beginning of the test is 20°C, and the temperature of point B' at the end of the test is 31°C. During the charging process at a 5C charging rate, the temperature rise of the second test point of the battery pack is 11°C.

[0284] According to the temperature test results of the above battery pack at a 5C charging rate, the temperature rise of the battery pack at the four test points is 15°C, 16°C, 13°C and 11°C. The lowest temperature rise is 11°C and the highest temperature rise is 16°C. Therefore, the temperature rise range of the battery pack at a 5C charging rate is 11°C to 16°C. Taking into account the ±3°C error in the test, the temperature rise range of the battery pack is 8°C to 19°C. In other words, when charged at a 5C charging rate, the temperature rise of the battery pack does not exceed 19°C.

[0285] According to the temperature test results of the above-mentioned battery pack at a 5C charging rate, when the capacity of the battery cell in the battery pack is 4Ah, the temperature rise at the two test points of the battery pack is 15°C and 16°C respectively. When the capacity of the battery cell in the battery pack is 11Ah, the temperature rise at the two test points of the battery pack is 13°C and 11°C respectively. It can be seen that the temperature rise of the battery pack varies depending on the capacity of the battery cell. At a 5C charging rate, the difference ranges from 2°C to 5°C. The temperature rise of the battery pack with small-capacity batteries is higher than that of the battery pack with large-capacity batteries.

[0286] In one embodiment, the battery pack includes 15 cells connected in series, each cell having a capacity of 4Ah. The battery pack is charged at a 10C charging rate according to the above test conditions to obtain a data curve of temperature change over time, such as Fig.25 As shown. According to this test curve, it can be seen that during the entire charging process, the temperature of the battery pack increases with time. The temperature change reflected by the solid line shows that the temperature at point A is 28°C at the beginning of the test and the temperature at point B is 47°C at the end of the test. When the battery pack is charged at a 10C charging rate, the temperature rise of the first test point is 19°C. The temperature change reflected by the dotted line shows that the temperature of point A' is 25°C at the beginning of the test and the temperature of point B' is 46°C at the end of the test. During the charging process at a 10C charging rate, the temperature rise of the second test point of the battery pack is 21°C.

[0287] In one embodiment, the battery pack includes 15 cells connected in series, each cell having a capacity of 11 Ah. The battery pack is charged at a 10C charging rate according to the above test conditions to obtain a data curve of temperature change over time, such as Fig.26 As shown. According to this test curve, it can be seen that during the entire charging process, the temperature of the battery pack will increase over time. The temperature change reflected by the solid line shows that the temperature at point A was 36°C at the beginning of the test and the temperature at point B was 47°C at the end of the test. During the charging process of the battery pack at a 10C charging rate, the temperature rise of the first test point was 11°C. The temperature change reflected by the dotted line shows that the temperature of point A' was 26°C at the beginning of the test and the temperature of point B' was 40°C at the end of the test. During the charging process at a 10C charging rate, the temperature rise of the second test point of the battery pack was 14°C.

[0288] According to the temperature test results of the above battery pack at a 10C charging rate, the temperature rise of the battery pack at the four test points was 19°C, 21°C, 11°C and 14°C respectively. The lowest temperature rise was 11°C and the highest temperature rise was 21°C. Therefore, the temperature rise range of the battery pack at a 10C charging rate is 11°C to 21°C. Taking into account the ±3°C error in the test, the temperature rise range of the battery pack is 8°C to 24°C. In other words, when charged at a 10C charging rate, the temperature rise of the battery pack does not exceed 24°C.

[0289] According to the temperature test results of the above-mentioned battery pack at a 10C charging rate, when the capacity of the battery cell in the battery pack is 4Ah, the temperature rise at the two test points of the battery pack is 19°C and 21°C respectively. When the capacity of the battery cell in the battery pack is 11Ah, the temperature rise at the two test points of the battery pack is 11°C and 14°C respectively. It can be seen that the temperature rise of the battery pack varies depending on the capacity of the battery cell. At a 10C charging rate, the difference ranges from 7°C to 8°C. The temperature rise of the battery pack with small-capacity batteries is higher than that of the battery pack with large-capacity batteries.

[0290] according to Figures 21 to 26 From the above test results, at the same charge rate, the temperature rise of the battery pack composed of large-capacity cells is different from the temperature rise of the battery pack composed of small-capacity cells. The temperature rise of the battery pack composed of large-capacity cells is lower than the temperature rise of the battery pack composed of small-capacity cells. In addition, the temperature rise difference between the two battery packs increases with the increase of the charge rate.

[0291] In one embodiment, the battery pack includes 15 cells connected in series, each cell having a capacity of 4Ah. The battery pack is discharged at a 5C discharge rate according to the above test conditions to obtain a data curve of temperature change over time, such as Fig. 27 As shown. According to this test curve, it can be seen that during the entire discharge process, the temperature of the battery pack will increase over time. The temperature change reflected by the solid line shows that the temperature at point A is 25°C at the beginning of the test and the temperature at point B is 39°C at the end of the test. During the discharge at a 5C discharge rate, the temperature rise of the first test point of the battery pack is 14°C. The temperature change reflected by the dotted line shows that the temperature at point A' is 23°C at the beginning of the test and the temperature at point B' is 38°C at the end of the test. At a 5C discharge rate, the temperature rise of the second test point of the battery pack is 15°C.

[0292] In one embodiment, the battery pack includes 15 cells connected in series, each cell having a capacity of 11 Ah. The battery pack is discharged at a 5C discharge rate according to the above test conditions to obtain a data curve of temperature change over time, such as Fig.28 As shown. According to this test curve, it can be seen that during the entire discharge process, the temperature of the battery pack increases with time. The temperature change reflected by the solid line shows that the temperature at point A is 25°C at the beginning of the test and the temperature at point B is 38°C at the end of the test. During the discharge at a 5C discharge rate, the temperature rise of the first test point of the battery pack is 13°C. The temperature change reflected by the dotted line shows that the temperature at point A' is 22°C at the beginning of the test and the temperature at point B' is 32°C at the end of the test. At a 5C discharge rate, the temperature rise of the second test point of the battery pack is 10°C.

[0293] According to the temperature test results of the above battery pack at a 5C discharge rate, the temperature rise of the battery pack at the four test points is 14°C, 15°C, 13°C and 10°C. The lowest temperature rise is 10°C and the highest temperature rise is 15°C. Therefore, the temperature rise range of the battery pack at a 5C discharge rate is 10°C to 15°C. Taking into account the ±3°C error in the test, the temperature rise range of the battery pack is 7°C to 18°C. In other words, when discharged at a 5C discharge rate, the temperature rise of the battery pack does not exceed 18°C.

[0294] According to the temperature test results of the above-mentioned battery pack at a 5C discharge rate, when the capacity of the battery cell in the battery pack is 4Ah, the temperature rise at the two test points of the battery pack is 14°C and 15°C respectively. When the capacity of the battery cell in the battery pack is 11Ah, the temperature rise at the two test points of the battery pack is 13°C and 10°C respectively. It can be seen that the temperature rise of the battery pack varies depending on the capacity of the battery cell. At a 5C discharge rate, the difference ranges from 1°C to 5°C. The temperature rise of a battery pack with a large-capacity battery cell is lower than that of a battery pack with a small-capacity battery cell.

[0295] In one embodiment, the battery pack includes 15 cells connected in series, each cell having a capacity of 4Ah. The battery pack is discharged at a discharge rate of 10C according to the above test conditions to obtain a data curve of temperature change over time, such as Fig.29 As shown. According to this test curve, it can be seen that during the entire discharge process, the temperature of the battery pack increases with time. The temperature change reflected by the solid line shows that the temperature at point A is 30°C at the beginning of the test and the temperature at point B is 49°C at the end of the test. During the discharge at a 5C discharge rate, the temperature rise of the first test point of the battery pack is 19°C. The temperature change reflected by the dotted line shows that the temperature at point A' is 28°C at the beginning of the test and the temperature at point B' is 48°C at the end of the test. At a 5C discharge rate, the temperature rise of the second test point of the battery pack is 20°C.

[0296] In one embodiment, the battery pack includes 15 cells connected in series, each cell having a capacity of 11Ah. The battery pack is discharged at a discharge rate of 10C according to the above test conditions to obtain a data curve of temperature change over time, such as Fig.30 As shown. According to this test curve, it can be seen that during the entire discharge process, the temperature of the battery pack will increase over time. The temperature change reflected by the solid line shows that the temperature at point A is 28°C at the beginning of the test and the temperature at point B is 43°C at the end of the test. During the discharge process at a discharge rate of 10C, the temperature rise of the first test point of the battery pack is 15°C. The temperature change reflected by the dotted line shows that the temperature at point A' is 25°C at the beginning of the test and the temperature at point B' is 38°C at the end of the test. At a discharge rate of 10C, the temperature rise of the second test point of the battery pack is 13°C.

[0297] According to the temperature test results of the above battery pack at a 10C discharge rate, the temperature rise of the battery pack at the four test points is 19°C, 20°C, 15°C and 13°C. The lowest temperature rise is 13°C and the highest temperature rise is 20°C. Therefore, the temperature rise range of the battery pack at a 10C discharge rate is 13°C to 20°C. Taking into account the ±3°C error in the test, the temperature rise range of the battery pack is 10°C to 23°C. In other words, when discharged at a 10C discharge rate, the temperature rise of the battery pack does not exceed 23°C.

[0298] According to the temperature test results of the above-mentioned battery pack at a 10C discharge rate, when the capacity of the battery cell in the battery pack is 4Ah, the temperature rise at the two test points of the battery pack is 19°C and 20°C respectively. When the capacity of the battery cell in the battery pack is 11Ah, the temperature rise at the two test points of the battery pack is 15°C and 13°C respectively. It can be seen that the temperature rise of the battery pack varies depending on the capacity of the battery cell. At a 10C discharge rate, the difference ranges from 4°C to 7°C. The temperature rise of a battery pack with a large-capacity battery cell is lower than that of a battery pack with a small-capacity battery cell.

[0299] according to Figures 27 to 30 According to the above test results, at the same discharge rate, the temperature rise of the battery pack composed of cells with large capacity is different from the temperature rise of the battery pack composed of cells with small capacity. The temperature rise of the battery pack composed of cells with large capacity is lower than the temperature rise of the battery pack composed of cells with small capacity. In addition, the temperature rise difference between the two battery packs increases with the increase of the discharge rate.

[0300] In at least one embodiment, the battery pack includes at least one battery cell. The battery pack is charged at a 3C rate and discharged at a 10C rate, and the temperature of the battery pack is obtained during charging and discharging for temperature testing. The test conditions include a test environment temperature of approximately 25°C, such as 25°C ± 3°C, or 20°C ± 3°C, or 30°C ± 3°C. In each of the following tests, the temperature at the test start point can be used to determine which of the above temperature ranges the test environment temperature falls in. No fan cools the battery pack during charging. Two test points are arranged inside the battery pack. The battery pack is first charged at a 3C rate, then discharged at a 10C rate, then charged at a 3C rate, and discharged at a 10C rate, and so on, until the temperature of the battery pack reaches a charging protection temperature or a discharge protection temperature. When the charging current is less than a preset current value, the single charging process ends. When the voltage of a single battery cell or the voltage of the entire battery pack is less than a preset voltage value, the single discharge process ends. The preset current value is greater than or equal to the current value corresponding to the 1C charging rate, and the preset voltage value is greater than or equal to 2.5V per battery cell. The charging protection temperature is 60°C, and the discharging protection temperature is 70°C. During the charge and discharge cycle, the temperature of the two test points of the battery pack is monitored to obtain a curve with time as the horizontal axis and temperature as the vertical axis. The solid line represents the temperature at the first test point, and the dotted line represents the temperature at the second test point.

[0301] In one embodiment, the battery pack includes 15 cells connected in series, each cell having a capacity of 4Ah. The battery pack is tested according to the test conditions described previously, and the obtained temperature variation curve over time is as follows: Fig.31 As shown. Fig.31In the figure, the temperature change from 0 to t1 represents 3C rate charging, t1 to t2 represents 10C rate discharging, t2 to t3 is used for 3C rate charging, and t3 to t4 represents 10C rate discharging.

[0302] During the 0 to t1 phase, the temperature at point A at the beginning of the solid line is 17°C, and the temperature at point B at the end of the solid line is 28°C; the temperature at point A' at the beginning of the dotted line is 17°C, and the temperature at point B' at the end of the dotted line is 27°C. It can be seen that at the end of the 3C rate charging process, the temperatures of both test points did not exceed the discharge protection temperature. Therefore, there is no need to wait for the temperature to drop after the charging process is completed, and the next discharge process can be performed immediately.

[0303] During the t1 to t2 stage, the temperature at point B at the beginning of the solid line is 28°C, and the temperature at point C at the end of the solid line is 50°C; the temperature at point B' at the beginning of the dotted line is 27°C, and the temperature at point C' at the end of the dotted line is 46°C. It can be seen that at the end of the 10C rate discharge process, the temperatures of both test points did not exceed the charge protection temperature. Therefore, there is no need to wait for the temperature to drop after the discharge process is completed, and the next charge process can be performed immediately.

[0304] During the t2 to t3 stage, the temperature of point C at the beginning of the solid line is 50°C, and the temperature of point D at the end of the solid line is 50°C; the temperature of point C' at the beginning of the dotted line is 46°C, and the temperature of point D' at the end of the dotted line is 47°C. It can be seen that at the end of the 3C rate charging process, the temperatures of both test points did not exceed the discharge protection temperature. Therefore, there is no need to wait for the temperature to drop after the charging process is completed, and the next discharge process can be performed immediately.

[0305] During the t3 to t4 stage, the temperature at point D at the beginning of the solid line is 50°C, and the temperature at point E at the end of the solid line is 65°C; the temperature at point D' at the beginning of the dotted line is 47°C, and the temperature at point E' at the end of the dotted line is 59°C. It can be seen that at the end of the 10C rate discharge process, the temperature of the two test points did not exceed the charging protection temperature. However, since the temperature is close to the charging protection temperature, immediately carrying out the next charging process will cause the battery pack to stop charging due to overheating, triggering the charging temperature protection. Therefore, it is necessary to wait for the temperature to drop before the next charging process can be carried out.

[0306] In one embodiment, the battery pack includes 15 cells connected in series, each cell having a capacity of 11 Ah. The battery pack is tested according to the test conditions described previously. The obtained temperature variation curve over time is as follows: Fig.32 As shown. Fig.32In the figure, the temperature change from 0 to t1 is used for 3C rate charging, t1 to t2 is used for 10C rate discharging, t2 to t3 is used for 3C rate charging, and t3 to t4 is used for 10C rate discharging.

[0307] During the 0 to t1 phase, the temperature at point A at the beginning of the solid line is 17°C, and the temperature at point B at the end of the solid line is 28°C; the temperature at point A' at the beginning of the dotted line is 17°C, and the temperature at point B' at the end of the dotted line is 25°C. It can be seen that at the end of the 3C rate charging process, the temperatures of both test points did not exceed the discharge protection temperature. Therefore, there is no need to wait for the temperature to drop after the charging process is completed, and the next discharge process can be performed immediately.

[0308] During the t1 to t2 stage, the temperature at point B at the beginning of the solid line is 28°C, and the temperature at point C at the end of the solid line is 47°C; the temperature at point B' at the beginning of the dotted line is 25°C, and the temperature at point C' at the end of the dotted line is 42°C. It can be seen that at the end of the 10C rate discharge process, the temperature of the two test points did not exceed the charging protection temperature. Therefore, there is no need to wait for the temperature to drop after the discharge process is completed, and the next charging process can be carried out immediately.

[0309] During the t2 to t3 stage, the temperature of point C at the beginning of the solid line is 47°C, and the temperature of point D at the end of the solid line is 53°C; the temperature of point C' at the beginning of the dotted line is 42°C, and the temperature of point D' at the end of the dotted line is 43°C. It can be seen that at the end of the 3C rate charging process, the temperatures of both test points did not exceed the discharge protection temperature. Therefore, there is no need to wait for the temperature to drop after the charging process is completed, and the next discharge process can be performed immediately.

[0310] During the t3 to t4 phase, the temperature at point D at the beginning of the solid line is 53°C, and the temperature at point E at the end of the solid line is 63°C; the temperature at point D' at the beginning of the dotted line is 43°C, and the temperature at point E' at the end of the dotted line is 53°C. It can be seen that at the end of the 10C rate discharge process, the temperature of the two test points did not exceed the charging protection temperature. However, since the temperature is close to the charging protection temperature, immediately carrying out the next charging process will cause the battery pack to stop charging due to overheating, triggering the charging temperature protection. Therefore, it is necessary to wait for the temperature to drop before carrying out the next charging process.

[0311] according to Fig.31 and Fig.32It can be seen from the test results that no matter what the capacity of the battery cells in the battery pack is, the temperature of the battery pack at the end of the first charging process will not exceed the discharge protection temperature; at the end of the first discharge process, the temperature of the battery pack does not exceed the charge protection temperature; at the end of the second charging process, the temperature of the battery pack does not exceed the discharge protection temperature; at the end of the second discharge process, the temperature of the battery pack does not exceed the charge protection temperature, but the temperature is close to the charge protection temperature, and it is necessary to wait for the temperature to drop before the next charging process. The difference in the capacity of the battery cells in the battery pack will only lead to a small difference in the temperature rise value, where the temperature rise of the battery pack with large-capacity cells is lower than that of the battery pack with small-capacity cells.

[0312] When operated at the above-mentioned charge and discharge rates, the battery pack can perform two consecutive charge and discharge cycles, one of which consists of a charging process and a discharging process. This feature allows the battery pack to be charged immediately when discharging at a large rate, that is, when the battery pack provides high power output to the power tool, once the battery pack discharge process is completed, without having to wait for the temperature to drop, thereby shortening the waiting time and enhancing the user experience.

[0313] The battery pack in the aforementioned embodiment has the characteristics of large charge rate, large discharge rate and low temperature rise, so that the battery pack can be continuously charged and discharged at a large rate without waiting between charging and discharging, thereby shortening the entire charge and discharge cycle of the battery pack. In an optional embodiment, the charge rate and discharge rate of the battery pack are 5C to 10C, and the total charge and discharge cycle time is 12 minutes to 30 minutes.

[0314] In at least one embodiment, the battery pack includes at least one battery cell. When the battery pack is charged at a 5C charge rate, when the current capacity of the battery pack reaches more than 80% of the rated capacity, the charge rate can be maintained at 5C. Optionally, when the current capacity of the battery pack reaches between 80% and 90% of the rated capacity, the charge rate can be maintained at 5C.

[0315] In one embodiment, the battery pack includes 15 cells connected in series, each cell having a capacity of 4Ah. The battery pack is charged at a 5C charge rate, and the charging current and capacity of the battery pack are monitored during charging to form Fig.33 The curve in Fig.33In the graph, the horizontal coordinate is the current capacity of the battery pack as a percentage of the rated capacity (SOC), and the vertical coordinate is the charging current of the battery pack. During the 0 to t1 stage, the charging current is 20A±0.5A, which corresponds to a charging rate of 5C. During the t1 to t2 stage, the charging current gradually decreases until it is less than 4A, which corresponds to a charging rate of 1C, at which point charging stops. Charging ends at time t2, when the current capacity of the battery pack is 100% of the rated capacity. The charging current begins to decrease from time t1, when the current capacity of the battery pack is 87% of the rated capacity. This means that when the current capacity of the battery pack is 87% of its rated capacity, the charging rate of the battery pack can still be maintained at 5C.

[0316] In one embodiment, the battery pack includes 15 cells connected in series, each cell having a capacity of 11 Ah. The battery pack is charged at a 5.5C charge rate, and the charging current and capacity of the battery pack are monitored during charging to form a Fig.34 The curve in Fig.34 In the graph, the horizontal coordinate is the percentage of the current capacity of the battery pack to the rated capacity (SOC), and the vertical coordinate is the charging current of the battery pack. During the 0 to t1 stage, the charging current is 60A±0.5A, which corresponds to a charging rate of 5.5C. During the t1 to t2 stage, the charging current gradually decreases until it is less than 11A, corresponding to a charging rate of 1C, at which time charging stops. Charging ends at time t2, when the current capacity of the battery pack is 100% of the rated capacity. The charging current starts to decrease from time t1, when the current capacity of the battery pack is 87% of the rated capacity. This means that when the current capacity of the battery pack is 87% of its rated capacity, the charging rate of the battery pack can still be maintained at 5.5C.

[0317] In at least one embodiment, the mobile charging device includes an energy storage unit 110, a charging module 120, and a charging port 130. Fig.35 As shown. The energy storage unit 110 is used to store direct current. The battery pack is detachably connected to the charging port 130. The charging module 120 electrically connects the energy storage unit 110 to the charging port 130, converts the energy of the energy storage unit 110 into energy suitable for charging the battery pack and outputs it to the charging port 130. The mobile charging device includes the energy storage unit 110, so that it can follow the user anywhere to charge the battery pack. In one usage scenario, the mobile charging device can be provided with wheels, and the user can carry it by pushing the wheels when carrying the mobile charging device. In another usage scenario, the mobile charging device can be installed on a car, and the car drives the mobile charging device to different workplaces.

[0318] In an alternative embodiment, if Fig.36As shown, the mobile charging device 400 is provided with a mounting hole 141 on the housing, and a mounting rail 210 is provided on the vehicle, so that the mobile charging device 400 is fixed to the vehicle by bolts 142, so that the mobile charging device 400 can move with the vehicle. The mobile charging device 400 also includes an anti-theft lock, through which it is fixed to the vehicle to prevent theft.

[0319] The number of charging ports may be one, two or more. The maximum output power of each charging port is 3Kw or higher. Therefore, each charging port can provide a charging rate of 5C or higher for the battery pack, so that the battery pack can be fully charged in a short time. Optionally, the maximum output power of each charging port is 3.6kW or greater. Optionally, the maximum output power of each charging port is 6kw or greater. Optionally, the maximum output power of each charging port is 7.2kW or greater. The maximum output power refers to the maximum power output of the charging port during the charging of the battery pack. In one example, the mobile charging device has only one charging mode, and the maximum output power output to one charging port is P1. In this case, the maximum output power of the charging port is P1. In another example, the mobile charging device has multiple charging modes, in the first charging mode, the maximum output power output to the charging port is P1, in the second charging mode, the maximum output power output to the charging port is P2, and in the third charging mode, the maximum output power output to the charging port is P3. In the case where the maximum value of P1, P2 and P3 is P3, the maximum output power of the charging port is P3.

[0320] In one embodiment, an energy system including a mobile charging device and a battery pack is provided. The basic composition of the mobile charging device is as described in the previous embodiment. The mobile charging device stores enough energy for a user of a garden power tool for a day's outdoor work. Optionally, the mobile charging device stores more than 500Wh of energy. Optionally, the number of battery packs is one, two or more. In one example, the number of battery packs is an even number, such as two, four, six... The battery packs numbered with even numbers are divided into two groups, A and B. When the battery pack of group A is used to discharge the power tool, the battery pack of group B is charged by the mobile charging device. The battery packs numbered with even numbers are divided into two groups, A and B. When the battery pack of group A is used to discharge the power tool, the battery pack of group B is charged by the mobile charging device. The two groups are then exchanged so that when group B is discharging the power tool, group A is charged by the mobile charging device, thereby providing uninterrupted power to the power tool.

[0321] In one embodiment, the mobile charging device has a maximum output power of 3.6kW from a single charging port. Optionally, the battery pack has a capacity of 4Ah and a rated voltage of 60V, and the charging port provides a charging rate of 10C or higher for the battery pack. Optionally, the battery pack has a capacity of 11Ah and a rated voltage of 60V, and the charging port provides a charging rate of 5C or higher for the battery pack.

[0322] In one embodiment, the mobile charging device has a maximum output power of 7.2kW for a single charging port. Optionally, the battery pack has a capacity of 4Ah, a rated voltage of 60V, and the charging port provides a charging rate of 10C or higher for the battery pack. Optionally, the battery pack has a capacity of 11Ah, a rated voltage of 60V, and the charging port provides a charging rate of 10C or higher for the battery pack.

[0323] In at least one embodiment, the mobile charging device includes a first charging mode and a second charging mode. In the first charging mode, the maximum output power of a single charging port is a first charging power, and in the second charging mode, the maximum output power of a single charging port is a second charging power. The first charging power is less than the second charging power. Optionally, the ratio of the second charging power to the first charging power is greater than 1.5. Optionally, the ratio of the second charging power to the first charging power is 2. In this embodiment, the maximum output power of the charging interface is the maximum output power corresponding to the mobile charging device in the second charging mode.

[0324] When the mobile charging device is in different charging modes, there are many solutions to achieve different charging powers output to the charging port. In one embodiment, the mobile charging device is configured with a first charging module and a second charging module. In the first charging mode, the first charging module works and outputs charging energy to the charging port, and in the second charging mode, the second charging module works and outputs charging energy to the charging port. In another embodiment, the mobile charging device includes only one charging module. In the first charging mode, the charging module operates in a low-power state and outputs low charging power to the charging port; in the second charging mode, the charging module operates in a high-power state and outputs high charging power to the charging port.

[0325] In other embodiments, Fig.37As shown, the mobile charging device includes an energy storage unit 110, a charging module 120 and a charging port 130. The charging module 120 includes a first charging module 121 and a second charging module 122. The charging port 130 includes a first charging port 131, a second charging port 132 and a third charging port 133. The mobile charging device has a first charging mode and a second charging mode. The mobile charging device includes four switches, namely switch K1, switch K2, switch K3 and switch K4. When switch K1 and switch K2 are turned on and switch K3 and switch K4 are turned off, the first charging module 121 and the second charging module 122 work independently of each other, and the mobile charging device is in the first charging mode. Among them, the first charging module 121 is connected to the first charging port 131 to provide charging energy for the first charging port 131; the second charging module 122 is connected to the second charging port 132 to provide charging energy for the second charging port 132. When the switches K1, K3 and K4 are turned on and the switch K2 is turned off, the first charging module 121 and the second charging module 122 are connected in parallel to jointly provide charging energy to the third charging port 133, and the mobile charging device is in the second charging mode. When the first charging module 121 and the second charging module 122 are connected in parallel, their output power is the sum of the output powers of the two charging modules. In addition, when the switches K1, K2 and K4 are turned on and the switch K3 is turned off, the first charging module 121 and the second charging module 122 are connected in parallel to jointly provide charging energy to the second charging port 132, which also puts the mobile charging device in the second charging mode. Optionally, the first charging module 121 and the second charging module 122 have the same maximum output power, both P1, then the maximum output power of the first charging port 131 and the second charging port 132 in the first charging mode is P1. In the second charging mode, the maximum output power of the third charging port 133 is 2*P1. The ratio of the maximum output power of the charging port in the second charging mode to the maximum output power of the charging port in the first charging mode is 2. Optionally, the third charging interface is not provided on the mobile charging device, and the first charging module 121 and the second charging module 122 are connected in parallel to jointly provide charging energy for the second charging port 132 or the first charging port 131. Optionally, only one charging port is provided on the mobile charging device. In the first charging mode, the first charging module 121 or the second charging module 122 provides charging energy for the charging port. In the second charging mode, the first charging module 121 and the second charging module 122 are connected in parallel to provide charging energy for the charging port. In an optional embodiment, the maximum output power of the first charging module 121 and the second charging module 122 is 3.6kw. In the first charging mode, the maximum output power of the first charging port 131 and the second charging port 132 are both 3.6kw.In the second charging mode, the maximum output power of the charging port is 7.2 kW. As mentioned above, the charging port may be one of the first charging port 131 , the second charging port 132 or the third charging port 133 .

[0326] There are many ways to trigger the switch between the first charging mode and the second charging mode. In one embodiment, the mobile charging device is provided with an operating component, such as a button, and the user manually triggers the operating component to switch the charging mode. Specifically, the mobile charging device is provided with a control module, which detects the state of the working component and controls the working state of the charging module according to the state of the working component to achieve the switching of the charging mode of the mobile charging device. In another embodiment, the mobile charging device identifies the information transmitted by the battery pack through the charging interface, such as the identity information of the battery pack or the charging request of the battery pack, and controls the working state of the charging module according to the information transmitted by the battery pack to achieve the switching of the charging mode of the mobile charging device.

[0327] In at least one embodiment, the energy storage unit of the mobile charging device includes a plurality of battery cells. The battery pack charged by the mobile charging device includes a plurality of battery cells. The battery cells of the mobile charging device have a first energy density, and the battery cells of the battery pack have a second energy density, the first energy density being higher than the second energy density. The energy density of a battery cell refers to the ratio of the product of the rated voltage and the rated capacity of the battery cell to the weight of the battery cell. The energy density of a battery cell refers to the ratio of the product of the rated voltage and the rated capacity of a single battery cell to the weight of the battery cell. The ratio of the total weight of the battery cells of the mobile charging device to the total weight of the battery cells of the battery pack is less than the ratio of the energy of the mobile charging device to the energy of the battery pack. The total weight of the battery cells of the mobile charging device refers to the sum of the weights of all the battery cells. The energy of the mobile charging device refers to the product of the rated voltage and the rated capacity of the energy storage unit formed by the electrical connection of the battery cells. The total weight of the battery cells of the battery pack is the sum of the weights of all the battery cells. The energy of the battery pack refers to the product of the rated voltage and the rated capacity of the energy storage unit formed by the electrical connection of the battery cells.

[0328] Optionally, the mobile charging device stores more energy than the battery pack. In an alternative embodiment, the energy stored in the battery pack is 60 Wh, and the energy stored in the mobile charging device is 500 Wh. In another alternative embodiment, the energy stored in the battery pack is 24 Wh, and the energy stored in the mobile charging device is 500 Wh. Optionally, the energy ratio of the mobile charging device to the battery pack is greater than 3. Optionally, the energy ratio of the mobile charging device to the battery pack is in the range of 3 to 22. Optionally, the energy ratio of the mobile charging device to the battery pack is in the range of 8 to 22. Such a setting allows the gardener to store the energy required for a day's work by carrying the mobile charging device, while configuring a smaller energy battery pack, and whenever and wherever the mobile charging device is used, transfer the energy from the mobile charging device to the battery pack by charging the battery pack, so as to power the power tool. Since the battery pack has small energy and is light in weight, it has better portability and is easier to directly power the power tool. The mobile charging device in turn supplements the small energy of the battery pack, which is not enough for a day's outdoor use. Another effect of this setting is that when the mobile charging device charges the battery pack at power P1, the battery cells of the mobile charging device discharge at a small discharge rate, but can provide a larger charging rate to charge the battery cells of the battery pack, thereby achieving fast charging of the battery pack. This means that battery cells with a smaller discharge rate can be used to charge battery cells with a larger charging rate, thereby reducing the cost of the battery cells of the mobile charging device. Specifically, the energy of the mobile charging device is set to W1, and the energy of the battery pack is set to W2. When the mobile charging device charges the battery pack at power P1, the discharge rate C1 of the mobile charging device or its battery cells = P1 / W1, and the charging rate C2 of the battery pack or its battery cells = P1 / W2. Since W1 > W2, C1 < C2. From the above formula, it can be seen that C2:C1 = W1:W2, that is, the ratio of the discharge rate of the mobile charging device to the charging rate of the battery pack is inversely proportional to the ratio of the energy of the mobile charging device to the energy of the battery pack. When W1:W2 > 3, C2:C1 > 3. In an optional embodiment, C2:C1 > 4. In an optional embodiment, C2:C1 is in the range of 4 to 12, and optionally, C2:C1 is in the range of 8 to 10.

[0329] In addition, compared with the battery cells of the battery pack, the battery cells of the mobile charging device have a higher energy density, allowing the mobile charging device to store a large amount of energy, but due to the high energy density of its battery cells, the overall weight of the mobile charging device will be reduced.

[0330] Optionally, the capacity of the mobile charging device is greater than the capacity of the battery pack. In an optional embodiment, the capacity of the battery pack is 11Ah and the capacity of the mobile charging device is 105Ah. In another optional embodiment, the capacity of the battery pack is 4Ah and the capacity of the mobile charging device is 105Ah. Optionally, the capacity ratio of the mobile charging device to the battery pack is greater than 3. Optionally, the capacity ratio of the mobile charging device to the battery pack is between 3 and 26. Optionally, the capacity ratio of the mobile charging device to the battery pack is between 8 and 26.

[0331] Optionally, the ratio of the cycle life of the battery cells of the battery pack to the battery cells of the mobile charging device is greater than 3. In one day's outdoor operation, the battery pack is charged and discharged 7 to 8 times, while the mobile charging device is charged and discharged 1 to 2 times a day. Optionally, under the same test conditions, the ratio of the cycle life of the battery cells of the battery pack to the battery cells of the mobile charging device is 4 to 17. Optionally, under the same test conditions, the ratio of the cycle life of the battery cells of the battery pack to the battery cells of the mobile charging device is 8 to 12. Therefore, the ratio of the cycle life of the battery pack relative to the portable charging device may also have the above relationship. Therefore, the life requirement of the mobile charging device is lower than the life requirement of the battery pack. As a result, the cost of the battery cells, electronic components and charging ports of the mobile charging device can be reduced.

[0332] Optionally, the maximum allowable charging rate of the cells of the mobile charging device is less than the maximum allowable charging rate of the cells of the battery pack. The charging scenario of the mobile charging device is the user's non-working hours, such as at night, or the user's lunch time. The charging urgency requirement is not high. The charging scenario of the battery pack is during the user's working hours, such as in the customer's garden, or on the way to the customer's garden, and the urgency of charging is high. If the maximum allowable charging rate of the battery pack is small and the charging is slow, it will increase the time the user has to wait for charging, thereby reducing the user's productivity. The maximum allowable charging rate of the cells of the mobile charging device is less than the maximum allowable charging rate of the cells of the battery pack, so that the user's productivity can be improved while reducing the cost of the cells of the mobile charging device.

[0333] Optionally, the internal resistance of each battery cell of the mobile charging device is greater than the internal resistance of each battery cell of the battery pack. The charge and discharge ratio of the battery cell of the mobile charging device is small, and the corresponding charging current and discharge current are also small. Therefore, even if the internal resistance of the battery cell of the mobile charging device is slightly large, it will not cause serious heating. On the contrary, the charging and discharge ratios of the battery cells of the battery pack are large, and the corresponding charging current and discharge current are also large. Therefore, only when the internal resistance of the battery cells of the battery pack is small enough will it not cause serious heating. The battery cells of the mobile charging device do not need to have a small internal resistance, which can reduce the cost of the battery cells of the mobile charging device.

[0334] In at least one embodiment, the rated capacity of the battery pack is 2Ah to 5Ah, and optionally, the capacity is 4Ah. The weight of the battery pack is 2.5kg to 3.5kg, and optionally, the weight is 3Kg. The maximum allowable charging rate is 10C to 12C. The battery pack includes 15 cells, and the voltage is 62.7V when fully charged.

[0335] In some other embodiments, the rated capacity of the battery pack is 10Ah to 12Ah, and optionally, the capacity is 11Ah. The weight of the battery pack is 7.3kg to 8.3kg, and optionally, the weight is 7.8kg. The maximum allowable charging rate is 10C to 12C. The battery pack includes 15 cells, and the voltage is 62.7V when fully charged.

[0336] In at least one embodiment, the mobile charging device has a rated capacity of 80Ah to 120Ah, optionally a capacity of 105Ah. The mobile charging device has a weight of 100kg to 120kg, optionally a weight of 110Kg. The voltage of the mobile charging device is about 48V.

[0337] In an optional embodiment, the mobile charging device includes an energy storage component and a charging component. The energy storage component includes a first shell and an energy storage unit disposed in the first shell. Optionally, the energy storage unit is a battery. The charging component includes a second shell and a charging module disposed in the second shell. The first shell and the second shell are disposed independently of each other, optionally separately, or the two shells are locked together by a locking device. The energy storage component and the charging component are detachably electrically connected via a cable. The charging component converts the direct current stored in the energy storage component into appropriate charging energy for charging the battery pack. The battery pack receives charging energy through a charging interface disposed on the second shell.

[0338] In at least one embodiment, any cell of the battery pack has a rated capacity of 4Ah and a rated voltage of 4V, and each has an energy of 16wh. In at least one embodiment, any cell of the battery pack has a rated capacity of 11Ah and a rated voltage of 4V, and each has an energy of 44wh.

[0339] In at least one embodiment, each battery cell in the battery pack has a capacity of 4Ah and a maximum allowable charge rate of 10C-12C, and a maximum charge current of up to 40A. Fig.38 As shown, the battery cell is non-cylindrical, and optionally, the battery cell is a sheet-like rectangular shape. Fig.38, W represents the width direction, and L represents the length direction. The battery includes a main body 11, a positive electrode ear 12, and a negative electrode ear 13. The ratio of the length to the height of the main body is greater than 10. The positive electrode ear 12 and the negative electrode ear 13 are located on the same side of the main body 11. Since the current passing through the battery is relatively small, the size of the positive electrode ear and the negative electrode ear is relatively small, and there is enough space on the same side of the main body 11 for the positive electrode ear 12 and the negative electrode ear 13 to use.

[0340] In at least one embodiment, each battery cell in the battery pack has a capacity of 11Ah and a maximum allowable charge rate of 10C-12C, with a maximum charge current of up to 110A. Fig.39 As shown, the battery cell is non-cylindrical, and optionally, the battery cell is a sheet-like rectangular shape. Fig.39 In the figure, W represents the width direction, and L represents the length direction. The battery includes a main body 11A, a positive electrode ear 12A, and a negative electrode ear 13A. The ratio of the length to the height of the main body is greater than 10. The positive electrode ear 12A and the negative electrode ear 13A are located on different sides of the main body 11A. Since the current passing through the battery cell is relatively large, the size of the positive and negative ears is relatively large, and there is not enough space on the same side of the main body 11A to place the positive electrode ear 12A and the negative electrode ear 13A, so the positive electrode ear 12A and the negative electrode ear 13A are placed on different sides of the main body 11A. Optionally, the positive electrode ear 12A and the negative electrode ear 13A are respectively located on a first side and a second side that are oppositely arranged, wherein the first side and the second side are perpendicular to the length direction of the main body 11A.

[0341] In one embodiment, the power tool system includes a power tool, a battery pack and a charging device. The charging device charges the battery pack at a rate not less than the discharge rate of the power tool to the battery pack. In other words, for the battery pack, the time it takes for the charging device to fully charge it is no longer than the time it takes for the power tool to empty it. In an optional embodiment, the charging device charges the battery pack at a rate greater than the discharge rate of the power tool to the battery pack. Optionally, the difference between the charging rate and the discharge rate is less than 2C, or the charging rate is greater than or equal to the discharge rate, or the charging rate is less than or equal to the discharge rate. In the case where the charging rate is less than the discharge rate and the difference between the two is less than 2C, considering that the power tool is not always working and there may be interruptions in the middle, it can also meet the requirement that one battery pack is empty and the other battery pack is fully charged, thereby achieving uninterrupted power supply to the power tool. Optionally, the maximum allowable discharge current of the battery pack is greater than 40A. In an optional embodiment, the charging device charges the battery pack at a rate of 5C or higher, and the power tool discharges the battery pack at a rate of 5C or lower. In an optional embodiment, the charging device has a charging rate of 10C or higher for the battery pack, and the power tool has a discharge rate of 4C or higher for the battery pack. In an optional embodiment, the charging power of the charging device to the battery pack is greater than the discharge power of the power tool to the battery pack. The charging rate and the discharge rate refer to the average charging rate and the average discharge rate, or the maximum charging rate and the maximum discharge rate. The charging power and the discharge power refer to the average charging power and the average discharge power, or the maximum charging power and the maximum discharge power.

[0342] In one embodiment, reference Fig.40 , the charging device is a mobile charging device 400. The battery pack includes at least one of the first type battery pack 101 or the second type battery pack 102. The electric tool includes at least one of a grass trimmer 301, a pruner 302, a hair dryer 303 and a backpack chain saw 205. According to the inventor's research on the working conditions of these tools, the average output power of the grass trimmer 301 is 0.8KW to 1.2KW, the average output power of the pruner 302 is 0.4KW to 0.6KW, the average output power of the hair dryer 303 is 1kW to 1.2KW, and the average output power of the backpack chain saw 205 is 1.2KW to 1.5KW. In order to ensure that the time for the mobile charging device 400 to fully charge the battery pack does not exceed the time for the electric tool to discharge the battery pack, the charging power of the mobile charging device 400 to the battery pack needs to be greater than or equal to 1.5kw. Optionally, the charging power of the mobile charging device 400 to the battery pack is greater than or equal to 3kw. Optionally, the charging power of the mobile charging device 400 for the battery pack is greater than or equal to 3.6 kW, wherein the charging power refers to the maximum charging power.

[0343] Optionally, the first type battery pack 101 has a rated voltage of 60V and a capacity of 11Ah, and the second type battery pack 102 has a rated voltage of 60V and a capacity of 4Ah. In this case, the average working time of the second type battery pack 102 for the lawn mower 301 is 60*4 / 1000 / (0.8-1.2)=0.2-0.3 hours, the average working time of the second type battery pack 102 for the pruning machine 302 is 60*4 / 1000 / (0.4-0.6)=0.4-0.6 hours, the average working time of the second type battery pack 102 for the hair dryer 303 is 60*4 / 1000 / (1-1.2)=0.2-0.24 hours, and the average working time of the second type battery pack 102 for the backpack chain saw 205 is 60*4 / 1000 / (1.2-1.5)=0.16-0.2 hours. The average working time of the first type battery pack 101 for the lawn mower 301 is 60*11 / 1000 / (0.8-1.2)=0.55-0.83 hours, the average working time of the first type battery pack 101 for the pruning machine 302 is 60*11 / 1000 / (0.4-0.6)=1.1-1.65 hours, and the average working time of the first type battery pack 101 for the hair dryer 303 is 60*11 / 1000 / (1-1.2)=0.55-0.66 hours. The average working time of the first type battery pack 101 for the backpack chain saw 205 is 60*11 / 1000 / (1.2-1.5)=0.44-0.55 hours. On the other hand, the battery pack can be charged at a rate of 5C or higher, which means that the first type battery pack 101 or the second type battery pack 102 can be charged at a rate of 5C and fully charged within 0.2 hours. Therefore, in most cases, the charging time of the battery pack is much shorter than the discharging time of the battery pack.

[0344] In one embodiment, reference Fig.40, the battery pack includes a first type battery pack 101 and a second type battery pack 102. The power tool includes a handheld power tool 300 and a wheeled or backpack power tool 200. The first type battery pack 101 supplies power to the wheeled or backpack power tool 200, and the second type battery pack 102 supplies power to the handheld power tool 300. The capacity of the first type battery pack 101 is greater than the capacity of the second type battery pack 102. The rated power of the wheeled or backpack power tool 200 is greater than the rated power of the handheld power tool 300. Optionally, the capacity of the first type battery pack 101 is 8Ah to 12Ah, and the weight is less than 8Kg. Optionally, the capacity of the second type battery pack 102 is 3.6Ah to 4Ah, and the weight is less than 3.5kg. Optionally, the first type battery pack 101 has a first charging and discharging port, and the second type battery pack 102 has a second charging and discharging port, and the first charging and discharging port and the second charging and discharging port are the same, so that the first type battery pack 101 and the second type battery pack 102 can both power the wheeled or backpack power tool 200 and the handheld power tool 300. In at least one embodiment, see Fig.40 The wheeled or backpack electric tool 200 includes a push lawn mower 201 and a backpack chain saw 205 . The handheld electric tool 300 includes a grass trimmer 301 , a pruning machine 302 , and a hair dryer 303 .

[0345] In at least one embodiment, reference Fig.40 , the mobile charging device 400 can charge the first type battery pack 101 and can also charge the second type battery pack 102. Optionally, the rated capacity of the first type battery pack 101 is different from the rated capacity of the second type battery pack 102. Optionally, the mobile charging device 400 charges the first type battery pack 101 at a first charging power and charges the second type battery pack 102 at a second charging power. Optionally, the first charging power and the second charging power are different. At the first charging power, the charging rate of the first type battery pack 101 is C1. At the second charging power, the charging rate of the second type battery pack 102 is C2. Optionally, C1 and C2 are the same. The rated capacity of the first type battery pack 101 is greater than the rated capacity of the second type battery pack 102. The first charging power is greater than the second charging power.

[0346] The content required to be protected in the optional technical solution is 1. A power supply system, comprising: The first battery pack; Second battery pack; An electric garden tool configured to be powered by the first battery pack or the second battery pack; A mobile charging device, which is configured to alternately charge the battery packs so that energy is continuously supplied to the electric garden tool, wherein the mobile charging device includes at least one charging port, the at least one charging port is configured to receive the first battery pack or the second battery pack, and The mobile charging device is configured to provide energy sufficient for multiple operations, and at least one charging port of the mobile charging device has a maximum output power greater than or equal to 3 kW, charging the first battery pack or the second battery pack at a charging rate of 5C. 2. The power supply system according to claim 1, characterized in that the mobile charging device includes at least one battery cell that provides direct current. 3 . The power supply system as claimed in claim 2 , wherein the energy density of the battery cell of the mobile charging device is greater than the energy density of the battery pack. 4 . The power supply system as claimed in claim 1 , wherein the energy of the mobile charging device is greater than the energy of the battery pack. 5 . The power supply system as claimed in claim 4 , wherein an energy ratio between the mobile charging device and the battery pack is greater than 3. 6 . The power supply system according to claim 3 , wherein a mass ratio between the battery cells of the mobile charging device and the battery cells of the battery pack is less than the energy ratio. 7. The power supply system as described in claim 2 is characterized in that the maximum life cycle of the battery cells of the mobile charging device is less than the maximum life cycle of the battery cells of the battery pack, wherein the ratio of the maximum life cycle of the battery cells of the battery pack to the maximum life cycle of the battery cells of the mobile charging device is greater than 3. 8. The power supply system as described in claim 1 is characterized in that the mobile charging device operates in a first charging mode or a second charging mode, when in the first charging mode, at least one charging port has a maximum output power of a first charging power, and when in the second charging mode, at least one charging port has a maximum output power of a second charging power, wherein the first charging power is less than the second charging power. 9. The power supply system as claimed in claim 8, characterized in that, for a 4Ah battery pack, the first charging power is 3.6kW, and the charging rate does not exceed 10C. 10 . The power supply system according to claim 8 , wherein, for an 11Ah battery pack, the first charging power is 3.6kW, and the charging rate is greater than 5C. 11. The power supply system according to claim 8, characterized in that, for an 11Ah battery pack, the second charging power is 7.2kW, and the charging rate does not exceed 10C. 12. The power supply system according to claim 1, characterized in that the mobile charging device has at least two charging modules, a single charging module has a maximum output power of 3.6 kW, and a plurality of single modules connected in parallel have a maximum output power of 7.2 kW. 13. The power supply system of claim 12, wherein the charging modules operate independently when in the first charging mode, and a plurality of single modules operate in parallel when in the second charging mode. 14. The power supply system according to claim 8, characterized in that a ratio of the second charging power to the first charging power is greater than or equal to 1.5. 15. The power supply system of claim 1, wherein the mobile charging device is configured to be connected to a vehicle using an anti-theft system. 16. The power supply system according to claim 1, wherein the maximum output power of the mobile charging device is at least 7000W. 17. The power supply system of claim 1, wherein the mass of the first battery pack is less than 3.5 kg and the capacity is 4 Ah, the mass of the second battery pack is less than 8 kg and the capacity is 11 Ah, and the mass of the mobile charging device is less than 130 kg and the capacity is at least 100 Ah. 18. The power supply system of claim 1, wherein each of the plurality of operations is located at a different geographical location. 19. The power supply system according to claim 1, wherein the plurality of tasks are a plurality of tasks that a worker is expected to complete in a day's work. 20 . The power supply system of claim 2 , wherein an internal resistance of each of the at least one battery cell of the mobile charging device is greater than an internal resistance of the first battery pack and the second battery pack. 21. A power supply system, comprising: Battery pack; an electric garden tool configured to be powered by the battery pack; and A mobile charging device comprises at least one charging port configured to charge the battery pack, wherein the at least one charging port has a maximum output power greater than 3000W and charges the battery pack at a charging rate of 5C. 22. The battery pack system according to claim 21, The mobile charging device comprises a plurality of batteries of a first type, The first battery pack and the second battery pack include a plurality of second type battery cells, and The first type of battery cells are charged faster than the second type of battery cells. 23. The battery pack system as described in claim 22 is characterized in that the maximum discharge rate of the first type of battery cell is lower than the maximum charge rate of the second type of battery cell. 24. The battery pack system as described in claim 23 is characterized in that the ratio of the maximum charge rate of the second type of battery cell to the maximum discharge rate of the first type of battery cell is not less than 4.

[0347] In another optional aspect, what is claimed is 1. An electric tool system, comprising: Power tools; and Battery pack, including: a housing configured to be connected to the power tool; and A battery cell is located in the shell, wherein the battery cell is charged faster than the battery cell is discharged. 2. The power tool system of claim 1, wherein the battery cell is charged at a charge rate of 10C and discharged at a rate of at least 4C. 3. The power tool system as described in claim 1 is characterized in that the battery cell has a maximum available discharge current of at least 40A. 4. The electric tool system as described in claim 1 is characterized in that the electric tool system includes a mobile charging device, the mobile charging device has a maximum output power of not less than 3.6 kW, and the rated power of the electric tool is not greater than 3 kW. 5. The electric tool system as described in claim 1 is characterized in that the capacity of the battery pack is greater than 4Ah, the charging rate is not less than 10C, and the charging time is less than 5 minutes. 6. The power tool system of claim 1, wherein the battery pack has a continuous discharge power in a range of about 0.4 kW to about 1.5 kW for at least 8 minutes. 7. The electric tool system as described in claim 1 is characterized in that when the battery pack is charged at a charging rate of 3C, the temperature of the battery pack when the charging is completed is lower than the discharge protection temperature, wherein when the battery pack is discharged at a discharge rate of 10C, the temperature of the battery pack when the discharge is completed is lower than the charging protection temperature. 8. The electric tool system according to claim 1 is characterized in that, when cycled twice, the battery pack is charged at a charging rate of 3C in the first cycle, and the battery pack temperature after the charging of the first cycle is completed is lower than the discharge protection temperature, and wherein when the battery pack is discharged at a discharge rate of 10C in the first cycle, the battery pack temperature at the time of the discharge of the first cycle is completed is lower than the charging protection temperature, and wherein when the battery pack is charged at a charging rate of 3C in the second cycle, and the battery pack temperature is lower than the discharge protection temperature when the charging of the second cycle is completed, wherein when the battery pack is discharged at a discharge rate of 10C in the second cycle, the battery pack temperature is lower than the charging protection temperature when the discharge of the second cycle is completed. 9 . The electric tool system as claimed in claim 1 , wherein the capacity of the first battery pack is smaller than the capacity of the second battery pack. 10. The power tool system of claim 1, wherein the first battery pack weighs less than 3.5 kg and contains 3.6 to 4 Ah. 11. The electric tool system as claimed in claim 1, characterized in that the weight of the second battery pack is less than 8 kg and the capacity is 8 Ah to 11 Ah. 12. The power tool system of claim 1, wherein the port for connecting the first battery pack to the power tool is the same as the port for connecting the second battery pack to the power tool. 13. The electric tool system as claimed in claim 1, characterized in that the electric tool system includes a charging device for charging the first battery pack and the second battery pack. 14. The power tool system of claim 13, wherein the first battery pack has a first capacity, and wherein the second battery pack has a second capacity. 15. The power tool system of claim 14, wherein the first battery pack is charged by a first charging power and the second battery pack is charged by a second charging power, wherein the first capacity is smaller than the second capacity and the first charging power is smaller than the second charging power. 16. The power tool system of claim 1, wherein the power tool is a handheld power tool; and wherein the battery pack has a capacity of at least 4 Ah. 17. The power tool system of claim 1, wherein the power tool is a wheeled power tool or a backpack power tool; and the capacity of the battery pack is at least 11 Ah. 18. An electric tool comprising: A battery pack, comprising: a housing configured to be connectable to the power tool; and At least one battery cell is located within the housing, wherein a charge rate of the battery cell is faster than a discharge rate of the battery cell. 19. The electric tool of claim 18, wherein the internal resistance of each of the at least one battery cell is less than or equal to 3 milliohms. 20. The electric tool according to claim 18, wherein the battery pack comprises a plurality of battery cells, wherein the plurality of battery cells are stacked in a longitudinal direction within the housing, and The distance between adjacent battery cells in the longitudinal direction is greater than 1 / 12 of the thickness of the battery cell. 21. The power tool of claim 18, wherein the first group of power garden tools are handheld power garden tools, and wherein the second group of power garden tools are wheeled power garden tools or backpack power garden tools. 22. An electric tool system, comprising: multiple battery packs; and A plurality of power tools, wherein each of the plurality of battery packs comprises: a housing configured to be connectable to an electric power tool among the plurality of electric power tools; and a battery cell within the housing, wherein the difference between the rate at which the battery cell can be charged and the rate at which the battery cell can be discharged is less than 2C, and The battery cell has a maximum available discharge current of at least 40A. 23. A method of operating a battery pack system, comprising charging the battery pack, wherein the battery pack is charged at a charge rate not exceeding 5C and discharged at a discharge rate lower than 5C. 24. The method of claim 23, comprising: for each worker of the plurality of workers: charging the second battery pack at the first work location when the corresponding worker uses the first battery pack; and using the second battery pack to power the garden power tools used by the corresponding workers at the second work location when the plurality of workers move to the second work location; and When the corresponding worker uses the second battery pack at the second work site, the first battery pack is charged at the second work site. 25. The method of claim 23, further comprising: (i) Arrival at the first work location; (ii) using a first battery pack to power an electric tool used at the first work location, wherein the first battery pack is fully charged; (iii) charging the second battery pack at the first work location; (iv) completing work at the first work location and proceeding to the second work location; (v) while at the second work location, placing the second battery pack in the power tool and using the power tool at the second work location; and (vi) While at the second working location, charging the first battery pack.

[0348] The battery cells of the battery packs in the embodiments and claims of the present application are new lithium-based battery cells. In some embodiments, the new battery cells are referred to as Type 2 battery cells. The new battery cells can be obtained from Suzhou Aimeide New Energy Materials Co., Ltd., No. 9 Haixin South Road, Nanfeng Town, Zhangjiagang City, Jiangsu Province, China. In some different embodiments, the battery cells have different capacities, but they have substantially the same chemical composition.

[0349] In the embodiments of the present application, energy refers to the product of the rated voltage and the rated capacity of a given energy storage unit. Cell, or single cell, or battery, all three terms refer to the cell located in the housing of the battery pack. The full meaning of temperature is the temperature value under the condition that the temperature is related to the value. Energy density refers to the weight energy density, and the unit is wh / kg. A cell with a rated voltage of 4V refers to a battery cell with a voltage of 4.2V±0.05 when fully charged. The surface temperature of the battery refers to the temperature of the battery housing. The surface temperature of the battery pack refers to the temperature of the battery pack housing. Charging or discharging protection temperature, temperature protection threshold, and charging or discharging temperature protection value, all three terms mean that once the temperature of the battery pack reaches this value, a protection mechanism will be triggered to stop charging or discharging the battery pack.

[0350] The various embodiments disclosed in this application can be used as independent embodiments, or they can be combined with other embodiments to form new embodiments. For example, different embodiments of battery packs are disclosed in this application, and different features of the battery packs are described under each embodiment, and the different features of these different embodiments can be combined with each other to form a new battery pack. Different characteristics include energy density, capacity, linear characteristics, different ranges of values, etc.

[0351] Identifiers such as "(a)", "(b)", "(i)", "(ii)" etc. are sometimes used for different elements or steps. These identifiers are used for clarity and do not necessarily specify the order of elements or steps.

[0352] The present invention has been described above by means of functional building blocks that illustrate the implementation of specific functions and their relationships. For ease of description, the boundaries of these functional building blocks have been arbitrarily defined in this article. Alternate boundaries can be defined as long as the specified functions and their relationships are properly performed.

[0353] The description of the foregoing specific embodiments will reveal the general nature of the invention so fully that others can easily modify and / or adapt various applications, such as specific embodiments, by applying the knowledge of those skilled in the art without undue experimentation and without departing from the general concept of the invention. Therefore, based on the teachings and guidance presented herein, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments. It should be understood that the wording or terminology herein is used for the purpose of description rather than limitation, so that the terms or wording of this specification will be interpreted by those skilled in the art based on the teachings and guidance.

[0354] The breadth and scope of the present invention should not be limited by any of the foregoing exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims

1. A battery pack configured to power an electric tool, characterized in that: The battery pack includes a housing configured to be connectable to the power tool; At least one battery cell is located in the housing. The charging rate of each of the at least one battery cell is greater than 5C, Each of the at least one battery cell has a capacity of at least 3.6 Ah, and The internal resistance of each of the at least one battery cell is less than or equal to 3 milliohms.

2. The battery pack according to claim 1, characterized in that: The charging rate is in the range of 8C to 12C.

3. The battery pack according to claim 1, characterized in that: The energy density of the battery cell is greater than 120Wh / Kg.

4. The battery pack according to claim 1, characterized in that: The battery pack includes a plurality of battery cells, and the internal resistance of the plurality of battery cells in the battery pack is less than 45 milliohms, and the plurality of battery cells have a capacity of at least 4 Ah.

5. The battery pack according to claim 1, characterized in that: The battery pack includes a plurality of battery cells, and the internal resistance of all of the battery cells in the battery pack is less than 13 milliohms, and the battery cells have a capacity of at least 11 Ah.

6. The battery pack according to claim 1, characterized in that: When the remaining capacity of the battery pack is between 80% and 90% of the rated capacity, the battery pack has a charge rate of 5C.

7. The battery pack according to claim 1, characterized in that: When the battery pack is charged at a rate of 3C and the ambient temperature is about 20°C, the temperature rise of the battery pack does not exceed 14°C.

8. The battery pack according to claim 1, characterized in that: When the battery pack is charged at a rate of 5C and the ambient temperature is about 20°C, the temperature rise of the battery pack does not exceed 19°C.

9. The battery pack according to claim 1, characterized in that: When the battery pack is charged at a rate of 10C and the ambient temperature is about 25°C, the temperature rise of the battery pack does not exceed 24°C.

10. The battery pack according to claim 1, characterized in that: When the battery pack is discharged at a rate of 5C and the ambient temperature is about 25°C, the temperature rise of the battery pack does not exceed 18°C.

11. The battery pack according to claim 1, characterized in that: When the battery pack is discharged at a rate of 10C and the ambient temperature is about 25°C, the temperature rise of the battery pack does not exceed 23°C.

12. The battery pack according to claim 1, characterized in that: When the battery pack is charged at a charge rate of 3C, the temperature of the battery pack when charging is completed is lower than the discharge protection temperature, and when the battery pack is discharged at a discharge rate of 10C, the temperature of the battery pack when discharging is completed is lower than the charge protection temperature.

13. The battery pack according to claim 12, characterized in that: When the cycle is repeated twice, the battery pack is charged at a charge rate of 3C in the first cycle, and the temperature of the battery pack is lower than the discharge protection temperature when the charging of the first cycle is completed, and when the battery pack is discharged at a discharge rate of 10C in the first cycle, the temperature of the battery pack is lower than the charge protection temperature when the discharging of the first cycle is completed; and when the battery pack is charged at a charge rate of 3C in the second cycle, the temperature of the battery pack is lower than the discharge protection temperature when the charging of the second cycle is completed, and when the battery pack is discharged at a discharge rate of 10C in the second cycle, the temperature of the battery pack is lower than the discharge protection temperature when the discharging of the first cycle is completed. When the battery pack is discharged at a discharge rate of, when the second cycle of discharge is completed, the battery pack temperature is lower than the charging protection temperature.

14. The battery pack according to claim 1, characterized in that: The battery pack is charged and discharged at a cycle time in a range of about 12 minutes to about 30 minutes; and wherein the charge rate and the discharge rate are in a range of about 5C to about 10C.

15. The battery pack according to claim 1, characterized in that: The life cycle of the battery pack is greater than 2500 cycles at a temperature range of 0°C to 45°C, the battery pack is charged at a charge rate of 5C, the battery pack is discharged at a discharge rate of 5C, and after 2500 cycles, the battery pack capacity retention rate is at least 75%.

16. The battery pack according to claim 1, characterized in that: The energy of each battery cell is not less than 16Wh.

17. The battery pack according to claim 1, characterized in that: The maximum voltage of the battery pack is not less than 60V, the maximum capacity of the battery pack is not less than 4Ah, and the number of cells in the battery pack is 15.

18. The battery pack according to claim 1, characterized in that: The maximum voltage of the battery pack is not less than 60V, the maximum capacity of the battery pack is not less than 10Ah, and the number of cells in the battery pack is 15.

19. The battery pack according to claim 1, characterized in that: The capacity of each of the at least one battery cell is 4 Ah, and the positive electrode tab and the negative electrode tab of each of the at least one battery cell are located on the same side.

20. The battery pack according to claim 1, characterized in that: Each of the at least one battery cell has a capacity of 11 Ah, and a positive electrode tab and a negative electrode tab of each of the at least one battery cell are located on two opposite sides.

21. The battery pack according to claim 1, characterized in that: The battery pack includes a plurality of battery cells; The plurality of battery cells are stacked in the housing along a longitudinal direction; and The distance between adjacent battery cells in the longitudinal direction is greater than 1 / 12 of the thickness of the battery cell.

22. A battery pack system, comprising: Multiple battery packs, each battery pack includes: a housing configured to be connected to the power tool; and at least one battery cell located in the housing, The charging rate of each of the at least one battery cell is greater than 5C, Each of the at least one battery cell has a capacity of at least 3.6 Ah, and The internal resistance of each of the at least one battery cell is less than or equal to 3 milliohms.

23. An electric tool comprising: Tool actuator; and A battery pack configured to provide power to the tool actuator, the battery pack comprising: a housing configured to be connectable to the power tool; and At least one battery cell is located in the housing. The charging rate of each of the at least one battery cell is greater than 5C, Each of the at least one battery cell has a capacity of at least 3.6 Ah, and The internal resistance of each of the at least one battery cell is less than or equal to 3 milliohms.

24. The electric tool according to claim 23, characterized in that This includes lawn mowers, pruners, blowers, top handle saws or chain saws.

25. A battery pack configured to power an electric tool, the battery pack comprising: a housing configured to be connected to the power tool; and At least one battery cell is located in the housing. The charging rate of each of the at least one battery cell is greater than 5C, and The energy density of each of the at least one battery cell is greater than 120Wh / kg, And wherein the voltage output from each of the at least one battery cell varies approximately linearly during discharge of the battery cell.

26. The battery pack configured to power an electric tool according to claim 25, characterized in that: When the battery cell is discharged at 10C, the slope difference between two adjacent points is less than 0.25, and the slope refers to the rate of change of the voltage output from each of the at least one battery cell with the charging state of each of the at least one battery cell, and the difference in the charging state of each of the at least one battery cell between the two adjacent points is less than 5%.

27. The battery pack according to claim 1, characterized in that: The battery cell has a sheet-like rectangular shape.

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