Low-temperature heating control method and battery pack

Abstract

The invention relates to a low-temperature control method and a battery pack, the battery pack comprises a shell, a battery pack and a control panel, the battery pack and the control panel are mounted in the shell, a plurality of cells are connected in series and / or in parallel to form the battery pack, and the battery pack is electrically connected with the control panel; the battery pack further comprises a temperature sensing unit, a heating unit and a temperature control unit which are connected to the control panel, the heating unit is installed on the periphery of the battery cell, the periphery of the battery pack is defined as an outer contour, and at least part of the heating unit is attached to the outer contour; and the heating unit receives the low-temperature heating signal and directly transmits heat energy to the battery cell. The heating unit is arranged in the battery pack to directly heat the battery cells, so that the adaptability of the battery pack in a low-temperature environment is improved, and the heating efficiency is high; meanwhile, the heating pad of the heating unit is wound on the periphery of each battery cell, does not occupy extra space, has the performance of thermal effect, vibration reduction, insulation and the like, is simple in assembly mode and does not need to be welded for many times.

Description

TECHNICAL FIELD

[0001] The present application relates to a low-temperature heating control method, in particular to a battery pack with the low-temperature heating control method. BACKGROUND

[0002] At present, electric tools use lithium ion batteries and lithium iron phosphate batteries. Due to its own temperature-sensitive chemical properties, the electrolyte used by lithium batteries is an organic liquid that will become viscous or even coagulate at low temperatures. The activity of lithium ions decreases at low temperatures, resulting in weaker battery discharge capacity, thereby significantly reducing the power and endurance of electric tools compared to normal temperature. And charging the battery pack in an environment with a temperature lower than the allowable temperature of the battery pack can easily cause the battery pack to produce lithium precipitation, causing damage to the battery pack, and in severe cases, the separator of the battery pack may be punctured, causing internal short circuit of the battery pack. If in a cold region, the performance of the battery pack will be greatly reduced in a low-temperature environment, and the service life of the battery pack will also be greatly reduced.

[0003] Low-temperature heating is the main method to improve battery performance, mainly including external heating and internal heating. External heating usually refers to a method of generating heat outside the battery by using air, liquid, phase change material or electric heating wire and transferring the heat to the battery, which has the advantages of high stability and easy control. But it has the disadvantages of low heating rate, low energy utilization rate and high thermal inconsistency. Internal heating method can overcome the above-mentioned shortcomings and provide a feasible method for battery low-temperature heating.

[0004] In the prior art, internal heating usually uses a heating film to heat. For the above structure, please refer to the Chinese invention patent No. CN111009633A disclosed on April 14, 2020, which discloses a battery pack with low-temperature heating function. At least one outer surface of each battery cell in the battery pack is attached with a heating film perpendicular to the stacking direction, and the heating film is controlled by a circuit board to heat the battery cell. However, the heating film can only be charged by the internal power of the battery pack, and when the internal power of the battery pack is too low, the heating film is difficult to function. Moreover, the installation process of the heating film is relatively complex, which needs to be welded with multiple pins, and is not convenient for assembly.

[0005] Therefore, it is necessary to provide an improved low-temperature heating control method and battery pack to overcome the defects in the prior art. SUMMARY

[0006] In view of the shortcomings of the prior art, the purpose of the present application is to provide a battery pack which is simple to assemble and can adapt to low-temperature environment.

[0007] The application solves the problems in the prior art and can adopt the following technical scheme: a low-temperature heating control method applied to a battery pack; the battery pack comprises a shell, a control panel mounted on the shell, a battery pack connected to the control panel, a temperature sensing unit, a heating unit, a temperature control unit and a voltage sensing unit,

[0008] The method comprises the following steps:

[0009] In step 1, the current temperature of the battery cell fed back by the temperature sensing unit is obtained, and when the current temperature is less than the preset low-temperature heating temperature, the voltage of the battery pack fed back by the voltage sensing unit is used to determine whether the battery pack is in a high-power state or a low-power state, and step 2 or step 3 is executed accordingly.

[0010] In step 2, in response to the activation of the display unit or the power-on of the power tool, the temperature control unit generates a low-temperature heating signal and turns on the discharge heating circuit, and the heating unit receives the low-temperature heating signal and directly transmits heat energy to the battery pack.

[0011] In step 3, in response to the power-on of the charging device, the temperature control unit generates a low-temperature heating signal and turns on the charging heating circuit, and the heating unit receives the low-temperature heating signal and directly transmits heat energy to the battery pack.

[0012] Further improvement is that when the current temperature is greater than the preset high-temperature power-off temperature, the temperature control unit generates a high-temperature power-off signal and turns off the discharge heating circuit or the charging heating circuit.

[0013] Further improvement is that the display unit is exposed to the shell, and the user adjusts the display unit to enter a heating mode or a non-heating mode; in response to the non-heating mode set by the display unit, the temperature control unit generates a high-temperature power-off signal and turns off the discharge heating circuit and the charging heating circuit.

[0014] Further improvement is that a plurality of battery cells are connected in series and / or in parallel to form the battery pack, the heating unit is attached to the outer periphery of the battery cell, and extends around the outer peripheral surface of at least one battery cell.

[0015] Further improvement is that the heating unit has a heating pad, an adhesive attached to the heating pad and an input end connected to the heating pad, the input end is electrically connected to the heating pad, the adhesive is arranged at the end of the heating pad, and the contact area between the heating pad and the battery cell is at least 3 times the contact area between the adhesive and the battery cell.

[0016] Further improvement scheme is that the input end is electrically connected to the control panel, and the temperature control unit is integrated in the control panel and controls the power-on and power-off of the input end.

[0017] The present application also solves the problems of the prior art by using the following technical scheme: a battery pack includes a shell, a battery pack and a control panel mounted on the shell, a plurality of battery cells are connected in series and / or parallel to form the battery pack, and the battery pack is electrically connected to the control panel; the battery pack further includes a temperature sensing unit, a heating unit and a temperature control unit connected to the control panel, the heating unit is mounted on the outer periphery of the battery cell, the outer periphery of the battery pack is defined as an external contour, the heating unit has an arc-shaped portion, at least part of the arc-shaped portion is connected to the external contour, and the temperature sensing unit is configured to detect the current temperature of the battery cell and / or the battery pack; the temperature control unit sets a preset low-temperature heating temperature and receives the current temperature, in response to the current temperature being less than the preset low-temperature heating temperature, the temperature control unit generates a low-temperature heating signal and turns on a discharge heating circuit or a charging heating circuit; and the heating unit receives the low-temperature heating signal and directly transmits heat energy to the battery cell.

[0018] Further improvement scheme is that the heating unit covers at least 1 / 80 of the surface area of any one battery cell.

[0019] Further improvement scheme is that the contact arc length between the heating unit and the any one battery cell is greater than 1.5π.

[0020] Further improvement scheme is that the battery pack has a battery cell support for mounting the battery cell, two battery cell supports are arranged at the end of the battery cell, the control panel is located above the battery cell support, and there is a gap between the control panel and the heating unit in the up-down direction.

[0021] Compared with the prior art, the present application has the following beneficial effects: by arranging the heating unit in the battery pack to directly heat the battery cell, the adaptability of the battery pack in a low-temperature environment is improved, and the heating efficiency is high; at the same time, the heating pad of the heating unit is wound around the outer periphery of each battery cell, without occupying additional space, and has the performance of heat effect, vibration reduction and insulation, and the assembly method is simple and does not require multiple welding; in addition, the control panel sets heating mode and non-heating mode to meet the seasonal needs of the battery pack, and in order to consider the battery pack's own power and performance, the heating pad can be heated by the charger or the battery pack itself. BRIEF DESCRIPTION OF DRAWINGS

[0022] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings:

[0023] Figure 1is a schematic diagram of an overall structure of the charging device of the present application;

[0024] Figure 2 is another schematic diagram of an overall structure of the charging device of the present application;

[0025] Figure 3 is Figure 1 is a schematic diagram of a structure of the battery pack shown in

[0026] Figure 4 is Figure 3 is a schematic diagram of a disassembled structure of the battery pack shown in

[0027] Figure 5 is Figure 4 is a schematic diagram of a structure of the battery pack shown in

[0028] Figure 6 is Figure 5 is a schematic diagram of another angle of the battery pack shown in

[0029] Figure 7 is Figure 5 is a sectional view of the battery pack shown in

[0030] Figure 8 is Figure 7 is a schematic diagram of a structure of the battery pack shown in

[0031] Figure 9 is Figure 8 is a schematic diagram of another angle of the battery pack shown in

[0032] Figure 10 is Figure 3 is a flowchart of the low-temperature heating control method of the battery pack shown in

[0033] Figure 11 is Figure 3 is an electronic block diagram of the low-temperature heating control method of the battery pack shown in

DETAILED DESCRIPTION

[0034] The present application will be further described below in conjunction with the accompanying drawings and embodiments.

[0035] The terms used in the present application are merely for the purpose of describing specific embodiments and are not intended to limit the present application. For example, the words "upper", "lower", "front", "back", "left", "right", and the like indicating the orientation or positional relationship based on the orientation or positional relationship shown in the drawings are merely for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device / element referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0036] Please refer to Figures 1 to 3As shown, the embodiment of the present application relates to a battery system 1000, which mainly comprises an electrical device and a battery pack, the battery pack is electrically and / or mechanically connected with the electrical device for power transmission during charging and discharging in actual use. The battery pack, commonly known as "secondary battery", can be installed in various electrical devices. The electrical device can be an electrically operated machine such as an electric drill, a lawn mower, a hair dryer, etc. powered by a motor, or a power consuming device such as a lamp, a radio, a speaker, etc. without a motor. Alternatively, the electrical device can be a charging device powered by the battery pack.

[0037] In the embodiment, the direction in which the battery pack is slid when being installed in the battery pack accommodating portion is referred to as the rear direction, and the direction in which the battery pack is slid when being detached from the battery pack accommodating portion is referred to as the front direction. In addition, when the battery pack is installed in the battery pack accommodating portion, the direction in which the battery pack accommodating portion is located when viewed from the front of the battery pack is referred to as the upward direction, and the direction opposite to the upward direction is referred to as the downward direction. Furthermore, the direction orthogonal to the front-rear direction and the upward-downward direction is referred to as the left-right direction.

[0038] In the embodiment, the battery system 1000 mainly comprises a battery pack 100, an electric tool 200 and a charging device 300. The electric tool is an electric wrench 200 powered by the battery pack 100, which is equipped with an impact function and is generally suitable for tightening or loosening screws and / or bolts. In other embodiments, the battery pack 100 can also be used in cooperation with other types of handheld electric tools, for example, other electric tools that can be used in application scenarios such as drilling, grinding and cutting; the charging device is a charger 300 that provides power to the battery pack 100, which can provide a variety of different sizes of current and can be suitable for fast charging scenarios.

[0039] In combination with Figure 4As shown, the battery pack 100 includes ten battery cells 21 disposed within the housing 1 and electrically coupled to the terminal block 9, the battery cells 21 for receiving or discharging electrical power. In the present embodiment, the ten battery cells 21 are arranged in series and parallel, each battery cell 21 having a nominal voltage of about four volts, such that the battery pack 100 has a nominal voltage of about twenty volts. In other embodiments, the battery pack 100 can include more or fewer battery cells 21, and the battery cells 21 can be arranged in series, in parallel, or in a combination of series and parallel. For example, the battery pack 100 can be arranged with three battery cells 21 in series, resulting in a nominal voltage of about 12V. In other embodiments, the battery cells 21 can have different nominal voltages, such as 3.6V, 3.8V, 4.2V, etc.; and can have different rated capacities, such as 1.2Ah, 1.3Ah, 2.0Ah, 2.4Ah, 2.6Ah, 3.0Ah, etc. In other embodiments, the battery pack 100 can have different nominal voltages, such as 10.8V, 14.4V, 40V, 56V, etc. The battery cells 21 in the present embodiment are lithium-ion battery cells, and in other embodiments, the battery cells 21 can have other suitable chemistries.

[0040] In the present embodiment, the battery pack 100 includes a housing 1, a battery pack 2 mounted within the housing 1, and a control board 3 and a temperature sensing unit 4, a heating unit 5, a temperature control unit 6, a voltage sensing unit 7, and a display unit 8 directly or indirectly connected to the control board 3. The ten battery cells 21 are arranged in series and parallel to form the battery pack 2, which is electrically connected to the control board 3 and outputs / inputs electrical power through the terminal block 9. In the present embodiment, the control board 3 is used to control the charging and discharging of the battery pack 2, and the control board 3 detects the remaining capacity of the battery pack 2 in real time and forces the battery pack 2 to shut down when the battery pack 2 enters an overcharged / overdischarged state, thereby prolonging the service life of the battery pack 100.

[0041] In the present embodiment, the housing 1 can be made of plastic or other composite materials, and the housing 1 has a first housing 11 and a second housing 12 and a receiving space formed between the first housing 11 and the second housing 12, the battery pack 2 being mounted within the receiving space, the first housing 11 and the second housing 12 being configured to be upper and lower covers, and the first housing 11 being an upper housing and the second housing 12 being a lower housing, and a matching structure can be provided between the upper housing and the lower housing to position and tightly connect the two housings by screws.

[0042] The first shell 11 has a cover 111, a first opening and a second opening 113 penetrating the cover 111 from top to bottom, and a plug-in port 114 formed on the upper surface of the cover 111 and matched with the battery containing part. The first opening and the second opening 113 are used to contain the operating member 101, which is fixed to the first shell 11 by a limiting structure, simple in structure and convenient to install. The plug-in port 114 is configured to be mechanically connected with the tool containing part 201 of the power tool 200 and / or the charging containing part 301 of the charger 300 in a plug-in direction. The terminal seat 9 is configured to connect the tool plug-in tab 203 of the power tool 200 and / or the charging plug-in tab 303 of the charger 300 to form an electrical connection to transmit power. The battery pack 100 is detachably mounted to the power tool 200 or the charging device 300 via the operating member 101 for stable and reliable connection to power the power tool 200 or output power from the charging device 300.

[0043] Specifically, the operating member 101 is mounted in the above-mentioned containing space and protrudes to the outside of the shell 1, facilitating the operator to press and unlock. The key 101a of the operating member 101 is accommodated in the first opening, and the latch 101b of the operating member 101 is accommodated in the second opening 113. The key 101a and the latch 101b are engaged in the first shell 11 in a manner movable in the up-down direction. The latch 101b is used to engage the tool latch groove of the power tool 200 and / or the charging latch groove of the charger 300.

[0044] In the embodiment, the second shell 12 is an upper open rectangular parallelepiped, which is mainly used to carry the battery pack 2 and prevent the occurrence of falling failure of the battery pack 2.

[0045] In combination Figures 5 to 9 As shown, the battery pack 2 is composed of ten battery cells 21 arranged in two rows and five columns. The battery pack 2 has a first battery cell group 2a and a second battery cell group 2b, both of which are arranged in the front-rear direction and aligned in the up-down direction. The first battery cell group 2a can be provided with five battery cells 21, and the second battery cell group 2b can also be provided with five battery cells 21. The extension direction of the battery cell 21 is parallel to the left-right direction. In other embodiments, the battery pack 2 can be provided with only a single first battery cell group 2a, and the battery pack 2 has only five battery cells 21, or more / less battery cells 21. In other embodiments, the battery pack 2 is provided with a plurality of first battery cell groups 2a, and the plurality of first battery cell groups 2a can be arranged staggered to meet the actual production design requirements.

[0046] The battery pack 2 further comprises a cell holder 23 for mounting the plurality of cells 21, a connecting plate 24 for electrically connecting the cells 21, and a pad 25 arranged on the outer periphery of the cell holder 23. The ten cells 21, the cell holder 23, the connecting plate 24, and the pad 25 are assembled to form the battery pack 2.

[0047] The cell holder 23 is configured to fix each cell 21 in place to prevent movement of the cell 21 in the accommodating space. The cell holder 23 is provided with a plurality of cylindrical holes for fixing the cells 21.

[0048] Specifically, the cell holder 23 comprises a first holder assembly for mounting the left end of the cell 21 and a second holder assembly for fixing the right end of the cell 21. The first holder assembly and the second holder assembly are detachably connected by buckles and / or screws. The first holder assembly and the second holder assembly do not completely wrap the cell 21, so that part of the surface of the cell 21 is exposed in the accommodating space, meeting the necessary heat dissipation and other performance requirements of the cell 21. The upper end surface of the cell holder 23 is provided with a plurality of rib positions and / or screw columns for mounting the control board 3. The control board 3 is arranged on the upper side of the cell holder 23 and is fixedly connected to the cell holder 23. There is a certain gap between the control board 3 and the cell 21 to prevent the cell 21 from transferring heat to the electrical components on the control board 3, thereby avoiding affecting the service life of the electrical components.

[0049] The connecting plate 24 can have a plurality of connecting plates 24. The connecting plate 24 comprises a positive connecting plate, a negative connecting plate, and four intermediate connecting plates. The positive connecting plate and the negative connecting plate output the voltage of the battery pack 2. One end of the plurality of connecting plates 24 is welded to the cell 21, and the other end is welded to the control board 3, so as to monitor the voltage of the single cell through the connecting plate.

[0050] In the present embodiment, the pad 25 can be one or more of a waterproof sheet, an insulating sheet, a damping sheet, and a flexible circuit board.

[0051] In order to enable the battery pack 2 to perform normal charging and / or discharging in a low-temperature or ultra-low-temperature environment, a heating unit 5 is additionally arranged on the battery pack 2. The heating unit 5 is attached to the outer periphery of the cell 21 and extends around the outer periphery of at least one cell 21. The heating unit 5 can directly transfer heat energy to the battery pack 2, so that the temperature of the battery pack 2 can be raised to a suitable temperature for charging / discharging in a short time.

[0052] The outer periphery of the battery pack 2 is defined by an outer contour 22, which is the contour shape of the ten battery cells 21 and is substantially wavy. The heating unit 5 has an arc-shaped portion with an inner diameter greater than or equal to the outer diameter of the battery cell 21, and at least part of the arc-shaped portion is fitted to the outer contour 22, so that the heating unit 5 and the battery pack 2 are closely fitted to reduce the space occupation, thereby avoiding the overall volume of the battery pack 2 being too large.

[0053] In the present embodiment, the heating unit 5 has a thin heating pad 51, an adhesive 52 mounted on one side of the heating pad 51, and an input end 53 connected to the heating pad 51. The heating pad 51 is a carpet-shaped object containing heating wires, with a thickness of less than 3 mm and a length greater than the actual length of the battery pack 100. On the one hand, the heating pad 51 can meet the heating requirements of the battery cell, and on the other hand, it can also play a role in vibration reduction and / or insulation. The heating pad 51 is wrapped around the outer periphery of each battery cell 21 to directly heat the battery cell 21, improving heating efficiency and uniformity. Specifically, the heating pad 51 covers at least 1 / 80 of the surface area of any one battery cell 21, and the contact arc length between the heating pad 51 and any one battery cell 21 is greater than 1.5π, ensuring sufficient contact between the heating pad 51 and the battery cell 21. In addition, the heating pad 51 is directly fixed to the battery cell 21 by the adhesive 52, which can effectively prevent the heating pad 51 from moving, and there is a gap between the heating pad 51 and the control board 3 to prevent direct contact between them and prevent the influence of heat on electronic components.

[0054] Preferably, only one heating pad 51 is used to at least partially wrap all the battery cells 21, as shown in Figure 7 As shown, the heating pad 51 is wrapped in a serpentine shape after wrapping the first battery cell group 2a, and then wrapped around the second battery cell group 2b. This can save the use of the heating pad 51, and also meet the heating requirements and space compactness. Specifically, the heating pad 51 can be wrapped along the front upper half circle of the first battery cell of the first battery cell group 2a, around the lower half circle of the second battery cell of the first battery cell group 2a, around the upper half circle of the third battery cell of the first battery cell group 2a, around the lower half circle of the fourth battery cell of the first battery cell group 2a, around 3 / 4 of the fifth battery cell of the first battery cell group 2a from the upper end, then wrapped to the upper rear half circle of the fifth battery cell of the second battery cell group 2b, around the lower half circle of the fourth battery cell of the second battery cell group 2b, around the upper half circle of the third battery cell of the second battery cell group 2b, around the lower half circle of the second battery cell of the second battery cell group 2b, and around the upper half circle of the first battery cell of the second battery cell group 2b, thereby completing the wrapping of the heating pad 51.

[0055] The heating pad 51 is attached to one side of the battery cell 21, and a sticky glue 52 is provided on the side of the heating pad 51 to fix the heating pad 51 and the battery cell 21. The sticky glue 52 can be provided on the front and back ends of the heating pad 51 to facilitate assembly and connection. The contact area of the sticky glue 52 with the battery cell 21 is as small as possible so as not to affect the heat dissipation of the battery cell 21. Further, the total contact area of the heating pad 51 with the battery cell 21 is at least 3 times the total contact area of the sticky glue 52 with the battery cell 21. The input end 53 is electrically connected to the heating wire inside the heating pad 51, and the input end 53 can be welded to the control panel 3, and the control panel 3 controls the power-on and power-off of the heating pad 51.

[0056] In combination Figure 10 and Figure 11 As shown in FIGS. 1, 2, 3, 4, 5, 6, 7, and 8, the battery pack 100 is configured to perform low-temperature charging on the battery group 2 through the temperature sensing unit 4, the heating unit 5, the temperature control unit 6, the voltage sensing unit 7, and the display unit 8, so that the battery pack 100 can also perform its own performance in a low-temperature environment or an ultralow-temperature environment, and the overall service life is prolonged.

[0057] In the present embodiment, the temperature control unit 6 is integrated in the control panel 3, and the assembly of additional components is reduced.

[0058] One end of the temperature sensing unit 4 is attached to any one of the battery cells 21 or a selected one of the battery cells 21, and the other end is electrically connected to the control panel 3 to provide the current temperature of the battery cell 21. The temperature sensing unit 4 can be a conventional NTC temperature sensor or other temperature measuring device.

[0059] One end of the voltage sensing unit 7 is also electrically connected to the control panel 3 to provide the real-time voltage of the battery cell 21. The voltage sensing unit 7 can be a connecting piece or other additional flexible auxiliary circuit board.

[0060] The low-temperature heating method of the battery pack 100 is as follows: the temperature sensing unit is configured to detect the current temperature of the battery cell 21 and / or the battery group 2, the temperature control unit 6 sets a preset low-temperature heating temperature and receives the current temperature information, and in response to the current temperature being less than the preset low-temperature heating temperature, the temperature control unit 6 generates a low-temperature heating signal and turns on the discharge heating circuit or the charging heating circuit; then the heating unit 5 receives the low-temperature heating signal and directly transmits heat energy to each battery cell 21.

[0061] In order to meet the needs of the use scene, the low-temperature control method can be switched to a heating mode or a non-heating mode through the display unit 8, considering the use environment of the battery pack 100. The display unit 8 is exposed to the outside of the shell 1, facilitating the user to adjust the battery pack 100 to be in the heating mode or the non-heating mode. The setting can facilitate the user to switch the seasonal heating needs in summer and winter.

[0062] In the present embodiment, when the user switches the battery pack 100 to the non-heating mode via the display unit 8, it can be predicted that the current ambient temperature is high, and no additional heating of the battery cells is needed. In order to save power and ensure the safety of the battery pack, the temperature control unit 6 generates a high-temperature power-off signal in response to the non-heating mode set by the display unit 8, and turns off the discharge heating circuit and the charging heating circuit to prevent the heating pad 51 from accidentally heating the battery cells.

[0063] When the user switches the battery pack 100 to the heating mode via the display unit 8, it can be predicted that the current ambient temperature is low, and additional heating of the battery cells is needed to fully utilize the charging and discharging performance of the battery pack 100. The user can activate the battery pack 100 to enter the pre-heating state, which can be activated by the operation button on the display unit 8 or by plugging the battery pack 100 into the charger 300 / electric tool 200 to automatically enter the pre-heating state.

[0064] Further, the control board 3 can then determine whether the battery pack 100 is in a low-power state or a high-power state based on the current power of the battery pack. When the power of any single battery cell 21 fed back by the voltage sensing unit 7 is less than 3.6V, or the power of the battery pack 100 is less than 18V, it is determined that the battery pack is in a low-power state, and the charger 300 needs to supply power to the heating pad 51. At this time, the power of the battery pack 100 cannot supply power to the heating pad 51, and the display unit 8 displays that the current heating pad 51 cannot be turned on. Conversely, it indicates that the battery pack is in a high-power state, and the battery pack 100 itself can supply power to the heating pad 51, and the display unit 8 displays that the current heating pad 51 can be turned on.

[0065] Specifically, according to the voltage of the battery pack fed back by the voltage sensing unit 7, if it is determined that the voltage of the battery pack is in a high-power state, the control board 3 obtains the current temperature of the battery cell 21 fed back by the temperature sensing unit 4. When the current temperature is less than the preset low-temperature heating temperature, the temperature control unit 6 generates a low-temperature heating signal and turns on the discharge heating circuit in response to the activation of the display unit 8 or the power-on of the electric tool. The heating unit 5 receives the low-temperature heating signal and directly transmits heat energy to the battery pack 2. When the current temperature is greater than the preset high-temperature power-off temperature, the temperature control unit 6 generates a high-temperature power-off signal and turns off the discharge heating circuit.

[0066] In addition, according to the voltage of the battery pack fed back by the voltage sensing unit 7, if it is judged that the state of the voltage of the battery pack is the low power state, the control panel 3 obtains the current temperature of the battery cell 21 fed back by the temperature sensing unit 4, when the current temperature is less than the preset low-temperature heating temperature, the temperature control unit 6 generates a low-temperature heating signal and turns on the charging heating circuit in response to the heating mode set by the display unit 8 and the power-on of the charging device, and the heating unit 5 receives the low-temperature heating signal and directly transmits the heat energy to the battery pack 2; when the current temperature is greater than the preset high-temperature power-off temperature, the temperature control unit 6 generates a high-temperature power-off signal and turns off the charging heating circuit.

[0067] In other embodiments, the control panel 3 can first obtain the current temperature of the battery cell 21 fed back by the temperature sensing unit 4, and then the control panel 3 obtains the voltage of the battery pack fed back by the voltage sensing unit 7 according to the voltage of the battery pack fed back by the voltage sensing unit 7 when the current temperature is less than the preset heating temperature.

[0068] If it is judged that the state of the voltage of the battery pack is the high power state, the temperature control unit 6 generates a low-temperature heating signal and turns on the discharging heating circuit in response to the activation of the display unit 8 or the power-on of the electric tool, and the heating unit 5 receives the low-temperature heating signal and directly transmits the heat energy to the battery pack 2; when the current temperature is greater than the preset high-temperature power-off temperature, the temperature control unit 6 generates a high-temperature power-off signal and turns off the discharging heating circuit.

[0069] If it is judged that the state of the voltage of the battery pack is the high power state, the temperature control unit 6 generates a low-temperature heating signal and turns on the discharging heating circuit in response to the activation of the display unit 8 or the power-on of the electric tool, and the heating unit 5 receives the low-temperature heating signal and directly transmits the heat energy to the battery pack 2; when the current temperature is greater than the preset high-temperature power-off temperature, the temperature control unit 6 generates a high-temperature power-off signal and turns off the discharging heating circuit.

[0070] The application directly heats the battery cell by arranging the heating unit 5 in the battery pack, improves the adaptability of the battery pack 100 in the low-temperature environment, and has high heating efficiency; at the same time, the heating pad 51 of the heating unit 5 is wound around the outer periphery of each battery cell, does not occupy extra space, has the performance of thermal effect, vibration reduction and insulation, and has a simple assembly method without multiple welding; in addition, the heating mode and the non-heating mode are set in the control panel to meet the seasonal needs of the battery pack, and in order to consider the power and performance of the battery pack, the heating pad can be heated by the charger 300 and can also be heated by the battery pack itself.

[0071] The application is not limited to the above specific embodiments. Those skilled in the art can easily understand that the low-temperature heating control method and the battery pack of the application have many other alternatives without departing from the principles and scope of the application. The protection scope of the application is defined by the contents of the claims.

Claims

1. A low-temperature heating control method, applied to a battery pack; characterized in that: The battery pack includes a housing, a control board mounted on the housing, a battery pack connected to the control board, a temperature sensing unit, a heating unit, a temperature control unit, and a voltage sensing unit. The method comprises: Step 1: Acquire the current temperature of the battery cell fed back by the temperature sensing unit. When the current temperature is less than the preset low-temperature heating temperature; and according to the voltage of the battery pack fed back by the voltage sensing unit, if the control board determines that the battery pack is in a high-power state, execute step 2 accordingly; if the control board determines that the battery pack is in a low-power state, execute step 3 accordingly; Step 2: In response to activation of the display unit or power-on of the power tool, the temperature control unit generates a low-temperature heating signal and connects the discharge heating circuit, and the heating unit receives the low-temperature heating signal and directly transfers heat energy to the battery pack; Step 3: In response to the charging device being powered on, the temperature control unit generates a low-temperature heating signal and connects the charging heating circuit. The heating unit receives the low-temperature heating signal and transfers heat energy directly to the battery pack.

2. The low-temperature heating control method according to claim 1, characterized in that: When the current temperature is greater than a preset high-temperature power-off temperature, the temperature control unit generates a high-temperature power-off signal and turns off the discharge heating circuit or the charging heating circuit.

3. The low-temperature heating control method according to claim 1, wherein: The display unit is exposed to the housing, and a user adjusts the display unit to enter a heating mode or a non-heating mode; in response to the non-heating mode set by the display unit, the temperature control unit generates a high-temperature power-off signal and turns off the discharge heating circuit and the charging heating circuit.

4. The low-temperature heating control method according to claim 1, wherein: A plurality of battery cells are connected in series and / or in parallel to form the battery pack. The heating unit is adhered to the outer periphery of the battery cells and extends around the outer periphery of at least one of the battery cells.

5. The low-temperature heating control method according to claim 1, wherein: The heating unit includes a heating pad, an adhesive mounted on the heating pad, and an input end connected to the heating pad, the input end is electrically connected to the heating pad, the adhesive is arranged at the end of the heating pad, and the contact area between the heating pad and the battery cell is at least 3 times the contact area between the adhesive and the battery cell.

6. The low-temperature heating control method according to claim 5, characterized in that: The input end is electrically connected to the control board. The temperature control unit is integrated into the control board and controls power on and power off of the input end.

7. A battery pack comprising a housing, a battery pack mounted on the housing, and a control board, wherein multiple cells are connected in series and / or in parallel to form a battery pack, and the battery pack is electrically connected to the control board; characterized in that: The battery pack also includes a temperature sensing unit, a heating unit and a temperature control unit connected to the control board. The heating unit is installed on the periphery of the battery cell, defining the periphery of the battery pack as an outer contour. The heating unit has an arc-shaped portion, at least part of which is connected to the outer contour. The temperature sensing unit is configured to detect the current temperature of the battery cell and / or the battery pack; the temperature control unit sets a preset low-temperature heating temperature and receives the current temperature. In response to the current temperature being lower than the preset low-temperature heating temperature, the temperature control unit generates a low-temperature heating signal and connects the discharge heating circuit or the charging heating circuit; the heating unit receives the low-temperature heating signal and transfers heat energy directly to the battery cell.

8. The battery pack according to claim 7, wherein: The heating unit covers at least 1 / 80 of the surface area of ​​any battery cell.

9. The battery pack according to claim 7, wherein: The contact arc length between the heating unit and any battery cell is greater than 1.5π.

10. The battery pack according to claim 7, wherein: The battery pack has a cell holder for mounting the cell, two cell holders are arranged at the ends of the cell, the control board is located above the cell holder, and there is a gap between the control board and the heating unit in the up and down directions.

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