Power battery charging method, device and electric vehicle

Abstract

The present invention discloses a charging method, device and electric vehicle for a power battery. The charging method for a power battery includes: after receiving an instruction for charging the power battery, obtaining the temperature value of the power battery; when determining that the power battery is currently in a no-current charging state according to the temperature value of the power battery, controlling the heater of the power battery to heat the power battery, and controlling the charging pile to charge the power battery without current. The charging method for a power battery can prevent the power battery from being charged at an extremely low temperature, thereby improving the safety and service life of the power battery.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to a method and device for charging a power battery and an electric vehicle. Background Art

[0002] In the electric vehicles in the related art, the power batteries used in them have their own characteristics. If the power batteries are charged at extremely low temperatures such as minus 25 degrees Celsius, the life and safety of the power batteries will be affected. For example, if the power battery is a lithium-ion battery, if the lithium-ion battery is charged at an extremely low temperature, lithium deposition will occur in the lithium-ion battery, reducing the life and safety of the battery. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, the first object of the present invention is to provide a charging method for a power battery to prevent the power battery from being charged at an extremely low temperature and to improve the life and safety of the power battery.

[0004] A second objective of the present invention is to provide a charging device for a power battery.

[0005] A third object of the present invention is to provide an electric vehicle.

[0006] To achieve the above-mentioned objectives, a first aspect of an embodiment of the present invention proposes a method for charging a power battery, comprising: after receiving an instruction to charge the power battery, obtaining a temperature value of the power battery; when determining that the power battery is currently in a no-current charging state according to the temperature value of the power battery, controlling a heater of the power battery to heat the power battery, and controlling a charging pile to charge the power battery without current.

[0007] To achieve the above-mentioned purpose, the second aspect of the embodiment of the present invention proposes a charging device for a power battery, comprising: an acquisition module, used to acquire a first temperature value of the power battery when receiving an instruction to charge the power battery; a control module, used to control the heater of the power battery to heat the power battery, and control the charging device to charge the power battery without current when determining that the power battery is currently in a no-current charging state based on the temperature value of the power battery.

[0008] In order to achieve the above-mentioned object, a third aspect of the present invention provides an electric vehicle, comprising the above-mentioned power battery charging device.

[0009] The power battery charging method, device and electric vehicle of the embodiment of the present invention can control the heater to heat the power battery while the charging pile does not charge the power battery when the power battery is judged to be in a no-current charging state according to the temperature value of the power battery, thereby preventing the charging pile from charging the power battery when the power battery is at an extremely low temperature and preventing the power battery from being damaged. In this way, the safety and service life of the power battery can be improved.

[0010] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a flow chart of a method for charging a power battery according to a first embodiment of the present invention;

[0012] Figure 2 is a working schematic diagram of a charging method for a power battery according to an example of the present invention;

[0013] Figure 3 is a flow chart of a method for charging a power battery according to a second embodiment of the present invention;

[0014] Figure 4 is a corresponding relationship diagram of a first voltage threshold and temperature of an example of the present invention;

[0015] Figure 5 is a flow chart of a method for charging a power battery according to a third embodiment of the present invention;

[0016] Figure 6 is a corresponding relationship diagram of a charging current standard value and temperature according to an example of the present invention;

[0017] Figure 7 is a flow chart of a method for charging a power battery according to a fourth embodiment of the present invention;

[0018] Figure 8 It is a structural block diagram of a charging device for a power battery according to an embodiment of the present invention. DETAILED DESCRIPTION

[0019] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0020] The following describes a method and device for charging a power battery and an electric vehicle according to embodiments of the present invention with reference to the accompanying drawings.

[0021] Figure 1 The figure is a flow chart of a method for charging a power battery according to an embodiment of the present invention.

[0022] like Figure 1 As shown, the method for charging the power battery includes the following steps:

[0023] S1, after receiving an instruction to charge the power battery, obtaining a temperature value of the power battery.

[0024] Specifically, a corresponding temperature sensor and a voltage sensor may be installed at a preset position of the power battery, and then when a command for charging the power battery is received, the temperature and voltage are acquired through the corresponding sensors. The power battery may be, for example, a battery pack.

[0025] The above-mentioned power battery charging instruction can be, for example, a charging pile sending a plug-in signal to the control unit, and the control unit determines whether the current state of the power battery supports charging and whether the current environment, such as the state of the charging pile, the current ambient temperature, etc., allows charging. If the current state of the power battery supports charging and the current environment allows charging, the control unit issues an instruction for the power battery to charge. The above-mentioned control unit is preferably a BMS (Battery Management System), and can also be other devices such as a computer set up by the user for control.

[0026] Alternatively, the user may also make a decision on his / her own whether to charge the battery, and then issue a command for charging the power battery.

[0027] It should be noted that the above temperature value is the temperature value obtained by the temperature sensor in real time; alternatively, the temperature value of the power battery can be first obtained by the temperature sensor in real time, and then the obtained temperature value is segmented according to a preset time length to obtain the lowest temperature value in each time period, and the lowest temperature value is used as the temperature value.

[0028] Furthermore, the current state of the power battery is determined according to the temperature value, and the demand current of the power battery is adjusted according to the current state of the power battery.

[0029] S2, when it is determined according to the temperature value of the power battery that the power battery is currently in a no-current charging state, the heater of the power battery is controlled to heat the power battery, and the charging pile is controlled to charge the power battery without current.

[0030] Specifically, the acquired temperature value of the power battery can be compared with a preset second heating temperature threshold, and when the temperature value of the power battery is less than or equal to the second heating temperature threshold, it is determined that the power battery is currently in an extremely low temperature state. The second heating temperature threshold has a value range of -25°C to -15°C, for example, -20°C.

[0031] Further, when it is determined that the power battery is in an extremely low temperature state, it is determined that the power battery is currently in a no-current charging state, the power battery heater is controlled to heat the power battery, and the charging pile is controlled to charge the power battery without current. The above heater can be, for example, an electric heating device, or a fuel heating device, a fuel cell heating device, a battery membrane heating device, a battery self-heating device, etc. The above no-current charging can be, for example, Figure 2 The charging pile is connected to the power battery under the control of the battery management system, and the current for charging the power battery is 0 ampere. The battery management system controls the heater so that the heater heats the power battery.

[0032] In this way, the power battery can be prevented from being charged at extremely low temperatures, and lithium deposition in the battery can be prevented, thereby improving the life and safety of the power battery.

[0033] In one embodiment of the present invention, Figure 3 As shown, the charging method of the power battery further includes:

[0034] S1, after receiving an instruction to charge the power battery, obtaining a temperature value of the power battery.

[0035] S211, determining whether the temperature value of the power battery is less than a first heating temperature threshold.

[0036] As an example, the control unit may obtain the temperature value of the power battery, and then the control unit determines whether the temperature value of the power battery is less than the first heating temperature threshold.

[0037] The first heating temperature threshold is a preset value, and its value range is 5°C to 15°C, and is preferably 10°C.

[0038] S212: Determine whether the temperature of the power battery is greater than a second heating temperature threshold.

[0039] Specifically, if the temperature value of the power battery is less than the first heating temperature threshold, it is determined whether the temperature value of the power battery is greater than the second heating temperature threshold.

[0040] S213: Determine whether a first voltage value of the power battery is greater than or equal to a first voltage threshold.

[0041] Specifically, if the temperature value of the power battery is greater than the second heating temperature threshold, the first voltage value of the power battery is acquired, and then it is determined whether the first voltage value of the power battery is greater than or equal to the first voltage threshold.

[0042] Among them, the above-mentioned first voltage value is the voltage value obtained by the voltage sensor in real time; alternatively, the voltage value of the power battery can be first obtained by the voltage sensor in real time, and then the obtained voltage value is segmented according to a preset time length, and the highest voltage value in each time period is obtained, and the highest voltage value is used as the first voltage value.

[0043] It should be noted that the first voltage threshold may be a voltage value corresponding to the temperature. For example, the corresponding relationship between the first voltage threshold and the temperature may be as follows: Figure 4 As shown; of course, the above-mentioned first voltage threshold can also be set by the user. Among them, the above-mentioned temperature is a temperature value obtained by a preset method. For example, the temperature value can be directly obtained, and then the first voltage threshold corresponding to the temperature value can be obtained; or, all temperature values ​​within a preset first time period can be obtained, and then the average value of the temperature value can be calculated to obtain the first voltage threshold corresponding to the average value; or, the average temperature of the location of the charging pile on that day can be obtained by a preset method such as through a meteorological station, and then the first voltage threshold corresponding to the average temperature can be obtained.

[0044] S214, adjusting the required current according to the operating power of the heater and the output power of the charging pile to ensure that no current flows into the power battery.

[0045] Specifically, when the temperature value of the power battery is less than the first heating temperature threshold and greater than the second heating temperature threshold, the first voltage value of the power battery is obtained; when the first voltage value of the power battery is greater than or equal to the first voltage threshold, it is determined that the power battery is currently in a no-current charging state. In this way, it can be achieved to determine that the power battery is currently in a no-current charging state according to the temperature value of the power battery.

[0046] Specifically, if the temperature value of the power battery is less than the first heating temperature threshold and greater than the second heating temperature threshold, and the first voltage value of the power battery is greater than or equal to the first voltage threshold, it means that the power battery is currently in a low temperature and high SOC (State of Charge) state. Since the charging cut-off voltage of the power battery will decrease in a low temperature state, if the power battery is judged to be in a low temperature and high SOC state, the power battery is controlled to be in a no-current charging state, and the power battery is only heated until the temperature value of the power battery is greater than or equal to the first heating temperature threshold. This avoids premature charging stop due to the reduction of the charging cut-off voltage of the power battery, and improves the user experience.

[0047] Optionally, if the temperature value of the power battery is less than or equal to the second heating temperature threshold, it means that the power battery is currently in an extremely low temperature state, and it is determined that the power battery is currently in a no-current charging state. In order to avoid damaging the power battery by charging the power battery when the power battery is in an extremely low temperature state, when the temperature value of the power battery is less than or equal to the second heating temperature threshold, the heater is controlled to heat the power battery, and the charging pile is controlled to charge the power battery without current.

[0048] Therefore, when the power battery is at an extremely low temperature, the power battery can be heated only until the temperature value of the power battery is greater than the second heating temperature threshold.

[0049] S215, controlling the heater to heat the power battery, and controlling the charging pile to charge the power battery with current.

[0050] Specifically, when the temperature value of the power battery is less than the first heating temperature threshold and greater than the second heating temperature threshold, and the first voltage value of the power battery is less than the first voltage threshold, the heater is controlled to heat the power battery, and the charging pile is controlled to charge the power battery with current.

[0051] Thus, when the power battery is in a low temperature and low SOC state, the power battery can be heated and charged simultaneously until the temperature value of the power battery is greater than or equal to the first heating temperature threshold or the first voltage value of the power battery is greater than or equal to the first voltage threshold.

[0052] S216, the charging pile charges and heats the power battery according to the normal charging control strategy.

[0053] Specifically, when the temperature value of the power battery is greater than or equal to the first heating temperature threshold, the charging pile is controlled to charge the power battery according to a normal charging control strategy until the power of the power battery reaches a preset power or the first voltage value of the power battery reaches a charging cut-off voltage.

[0054] S217, the power of the power battery reaches a preset power or the first voltage value of the power battery reaches a charging cut-off voltage.

[0055] In one embodiment of the present invention, Figure 5 As shown, the above-mentioned control charging pile charges the power battery with current, including:

[0056] S221, obtaining a first current flowing through the power battery.

[0057] Specifically, a current sensor may be installed at a preset position of the power battery, and then the first current flowing into the power battery may be acquired by using the current sensor.

[0058] Optionally, the current value output by the charging pile may also be obtained. For example, the current value output by the charging pile may be obtained by using the interactive information between the control unit and the charging pile.

[0059] S222: Determine a charging current standard value of the power battery according to the temperature value of the power battery.

[0060] Specifically, the corresponding relationship between the charging current standard value and the temperature of the power battery can be obtained in advance, for example, Figure 6 If the temperature is less than or equal to the second heating temperature threshold, the charging current standard value is zero; if the temperature is greater than the second heating temperature threshold and less than the first heating temperature threshold, the charging current standard value increases with the increase of the temperature; if the temperature is greater than or equal to the first heating temperature threshold, the charging current standard value is a certain value.

[0061] Furthermore, the charging current standard value of the power battery is determined according to the temperature value of the power battery and the corresponding relationship between the charging current standard value of the power battery and the temperature.

[0062] S223, determining whether the absolute value of the current difference between the first current flowing into the power battery and the standard value of the charging current is greater than a first current error threshold.

[0063] S224, determining whether the first current is a charging current.

[0064] Specifically, if the absolute value of the current difference between the first current flowing into the power battery and the standard value of the charging current is greater than the first current error threshold, the type of the first current is determined, specifically, whether the first current is a charging current can be determined. Thus, the standard value of the charging current can be adjusted according to the type of the first current, and the adjusted standard value of the charging current can be used as the charging demand current of the power battery, and the charging pile can be controlled to charge the power battery with the charging demand current.

[0065] Of course, the first current flowing through the power battery can also be obtained, and the type of the first current can be determined; and then the charging current standard value of the power battery can be determined according to the temperature of the power battery. Therefore, when the absolute value of the current difference between the first current and the charging current standard value is greater than the first current error threshold, the charging current standard value can be adjusted according to the type of the first current; and when the absolute value of the current difference between the first current and the charging current standard value is greater than the first current error threshold, the charging current standard value can be adjusted according to the type of the first current; and then the adjusted charging current standard value is used as the charging demand current of the power battery, and the charging pile is controlled to charge the power battery with the charging demand current.

[0066] It should be noted that if the first current is a charging current, it means that the charging pile is charging the power battery.

[0067] S225, lowering the current charging current standard value.

[0068] Specifically, when the first current is a charging current and the first current is greater than a standard value of the charging current, the standard value of the charging current is reduced at a first rate.

[0069] The first rate of reducing the charging current standard value is in the range of 0.5A / 3S to 1.5A / 3S, for example, 1A / 3S. The maximum allowable reduction of the charging current standard value can also be set, for example, the maximum allowable reduction of the charging current standard value can be set to 20A, that is, if the charging current standard value is greater than 20A, it cannot be reduced.

[0070] Optionally, when the first current is a charging current and is less than a standard value of the charging current, the standard value of the charging current is increased at a second rate, and the second rate for increasing the standard value of the charging current ranges from 0.5A / 10S to 1.5A / 10S, for example, it may be 1A / 10S.

[0071] S226, determining whether the first current is a discharge current, and determining whether the first current is greater than a first discharge current threshold.

[0072] Specifically, if the first current is not a charging current, it is determined whether the first current is a discharging current, and it is determined whether the first current is greater than a first discharging current threshold.

[0073] The first discharge current threshold has a value range of 0.5A to 1.5A, for example, 1A.

[0074] S227, increase the current charging current standard value.

[0075] Specifically, when the first current is a discharge current and the first current is greater than or equal to a preset discharge current threshold, the charging current standard value is increased at a third rate.

[0076] It should be noted that if the first current is less than the standard value of the charging current, the standard value of the charging current is increased at a preset rate, and the range of the rate of increasing the standard value of the charging current is 0.5A / 10S to 1.5A / 10S, for example, it can be 1A / 10S. The maximum allowable reduction of the standard value of the charging current can also be set to 20A, that is, if the standard value of the charging current is greater than 20A, it cannot be reduced.

[0077] S228, maintaining the charging current standard value of the power battery.

[0078] Specifically, when the absolute value of the current difference between the first current and the charging current standard value is less than or equal to the first current error threshold, the charging current standard value is used as the charging demand current of the power battery, and the charging pile is controlled to charge the power battery with the charging demand current.

[0079] Alternatively, when the first current is not a discharge current, or the first current is not greater than a first discharge current threshold, the charging current standard value of the power battery is maintained, and the charging current standard value is used as the charging demand current of the power battery, thereby controlling the charging pile to charge the power battery with the charging demand current.

[0080] In one embodiment of the present invention, see Figure 7 After executing the process of controlling the heater to heat the power battery and controlling the charging pile to charge the power battery, the power battery charging method further includes:

[0081] S31, obtaining the time of executing the process and obtaining the temperature rise of the power battery.

[0082] Specifically, after the process of controlling the heater to heat the power battery and controlling the charging pile to charge the power battery is executed, the time of executing the process can be obtained, and the temperature rise of the power battery can be obtained. The charging pile charging the power battery includes both the charging pile charging the power battery without current and the charging pile charging the power battery with current.

[0083] As an example, the control unit may record the time of executing the process through an internal counter, and record the temperature rise of the power battery through a temperature sensor.

[0084] S32, determining whether the time for executing the process reaches a first preset time.

[0085] The first preset time has a value range of 50 minutes to 70 minutes, for example, 60 minutes.

[0086] S33, determining whether the temperature value of the power battery is less than a first heating temperature threshold, and determining whether the temperature rise of the power battery is less than the first temperature rise threshold and whether it lasts for a second preset time.

[0087] Specifically, if the execution time of the process reaches the first preset time, it is determined whether the temperature value of the power battery is less than the first heating temperature threshold, and whether the temperature rise of the power battery is less than the first temperature rise threshold and whether it lasts for a second preset time.

[0088] Among them, the value range of the above-mentioned first heating temperature threshold is 5°C to 15°C, for example, it can be 10°C; the value range of the above-mentioned first temperature rise threshold is 2.5°C / 60min to 3.5°C / 60min, for example, it can be 3°C / 60min.

[0089] Optionally, the temperature sensor installed on the power battery can also be used to obtain the temperature of the power battery at the second preset time, and then the average value of the temperature can be calculated to determine whether the average is less than the first heating temperature threshold. At the same time, the temperature rise of the power battery can also be calculated using the average value. The second preset time can be, for example, 10 seconds.

[0090] S34, exiting the process of controlling the heater to heat the power battery and controlling the charging pile to charge the power battery.

[0091] Specifically, after the execution time of the process reaches the first preset time, if the temperature value of the power battery is less than the first heating temperature threshold and the temperature rise of the power battery is less than the first temperature rise threshold and lasts for the second preset time, the above process is exited.

[0092] S35, continuing the process of controlling the heater to heat the power battery and controlling the charging pile to charge the power battery.

[0093] Specifically, if the execution time of the process does not reach the first preset time, or if any one of the temperature value of the power battery is less than the first heating temperature threshold, the temperature rise of the power battery is less than the first temperature rise threshold, and the second preset time is not satisfied, then the process of controlling the heater to heat the power battery and controlling the charging pile to charge the power battery continues.

[0094] It should be noted that if it is judged to continue the process of controlling the heater to heat the power battery and controlling the charging pile to charge the power battery, the time of executing the process will be cleared while judging to continue the process; for example, if the time of executing the process is recorded by the control unit through an internal counter, the time of executing the process recorded by the counter will be cleared while judging to continue the process.

[0095] In summary, the power battery charging method of the embodiment of the present invention can only heat the power battery when the power battery is in an extremely low temperature state, thereby improving the life and safety of the power battery. It can also control only the power battery to be heated when the power battery is in a low temperature and high SOC state, thereby avoiding premature charging stop due to the reduction of the charging cut-off voltage of the power battery, thereby improving the user experience. It can also dynamically adjust the demand current of the power battery, thereby better controlling the charging of the power battery, further improving the user experience.

[0096] Figure 8 It is a structural block diagram of a charging device for a power battery according to an embodiment of the present invention.

[0097] like Figure 8 As shown, the power battery charging device 30 includes an acquisition module 301 and a control module 302 .

[0098] Specifically, the acquisition module 301 is used to acquire the temperature value of the power battery when receiving an instruction to charge the power battery; the control module 302 is used to control the power battery heater to heat the power battery and control the charging device to charge the power battery without current when determining that the power battery is currently in a no-current charging state based on the temperature value of the power battery.

[0099] It should be noted that, for other specific implementations of the power battery charging device of the embodiment of the present invention, reference may be made to the above-mentioned power battery charging method.

[0100] The power battery charging device of the embodiment of the present invention can heat only the power battery when the power battery is in an extremely low temperature state, thereby improving the life and safety of the power battery. It can also control only the power battery to be heated when the power battery is in a low temperature and high SOC state, thereby avoiding premature charging stop due to the reduction of the charging cut-off voltage of the power battery, thereby improving the user experience. It can also dynamically adjust the demand current of the power battery, thereby better controlling the charging of the power battery, further improving the user experience.

[0101] Furthermore, the present invention provides an electric vehicle.

[0102] In an embodiment of the present invention, an electric vehicle includes the above-mentioned power battery charging device.

[0103] The electric vehicle of the embodiment of the present invention can heat only the power battery when the power battery is in an extremely low temperature state through the above-mentioned power battery charging device, thereby improving the life and safety of the power battery. It can also control only the power battery to be heated when the power battery is in a low temperature and high SOC state, thereby avoiding premature charging stop due to the reduction of the charging cut-off voltage of the power battery, thereby improving the user experience. It can also dynamically adjust the demand current of the power battery, thereby better controlling the charging of the power battery, further improving the user experience.

[0104] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0105] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0106] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0107] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0108] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0109] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0110] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0111] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for charging a power battery, characterized in that: include: After receiving an instruction to charge the power battery, obtaining a temperature value of the power battery; When it is determined according to the temperature value of the power battery that the power battery is currently in a no-current charging state, controlling the heater of the power battery to heat the power battery, and controlling the charging pile to charge the power battery without current; When the temperature value of the power battery is less than the first heating temperature threshold and greater than the second heating temperature threshold, and the first voltage value of the power battery is less than the first voltage threshold, controlling the heater to heat the power battery, and controlling the charging pile to charge the power battery with current; The controlling the charging pile to charge the power battery with current includes: obtaining a first current flowing through the power battery and determining the type of the first current; determining a charging current standard value of the power battery according to the temperature of the power battery; when the absolute value of the current difference between the first current and the charging current standard value of the power battery itself is greater than a first current error threshold, adjusting the charging current standard value according to the type of the first current; using the adjusted charging current standard value as the charging demand current of the power battery, and controlling the charging pile to charge the power battery with the charging demand current; The adjusting the charging current standard value according to the type of the first current includes: When the first current is a charging current and the first current is greater than the charging current standard value, reducing the charging current standard value at a first rate; When the first current is a charging current and the first current is less than the charging current standard value, increasing the charging current standard value at a second rate; When the first current is a discharge current and the first current is greater than or equal to a preset discharge current threshold, the charging current standard value is increased at a third rate.

2. The method for charging a power battery according to claim 1, characterized in that: Determining, according to the temperature value of the power battery, that the power battery is currently in a no-current charging state includes: When the temperature value of the power battery is less than a first heating temperature threshold and greater than a second heating temperature threshold, acquiring a first voltage value of the power battery; When the first voltage value of the power battery is greater than or equal to a first voltage threshold, it is determined that the power battery is currently in a no-current charging state.

3. The method for charging a power battery according to claim 2, characterized in that: Determining, according to the temperature value of the power battery, that the power battery is currently in a no-current charging state, further comprising: When the temperature value of the power battery is less than or equal to the second heating temperature threshold, it is determined that the power battery is currently in a no-current charging state.

4. The method for charging a power battery according to claim 2, characterized in that: The method further comprises: When the temperature value of the power battery is greater than or equal to the first heating temperature threshold, the charging pile is controlled to charge the power battery according to a normal charging control strategy until the power of the power battery reaches a preset power or the first voltage of the power battery reaches a charging cut-off voltage.

5. The method for charging a power battery according to claim 1, characterized in that: The controlling the charging pile to charge the power battery with current also includes: When the absolute value of the current difference between the first current and the charging current standard value is less than or equal to the first current error threshold, the charging current standard value is used as the charging demand current of the power battery, and the charging pile is controlled to charge the power battery with the charging demand current.

6. The method for charging a power battery according to any one of claims 1 to 4, characterized in that: After executing the process of controlling the heater to heat the power battery and controlling the charging pile to charge the power battery, the method further includes: Obtaining the time for executing the process and obtaining the temperature rise of the power battery; After the execution time of the process reaches a first preset time, if the temperature value of the power battery is less than the first heating temperature threshold and the temperature rise of the power battery is less than the first temperature rise threshold and lasts for a second preset time, the process is exited.

7. A power battery charging device, the power battery charging device is used to implement the power battery charging method according to any one of claims 1 to 6, characterized in that: include: An acquisition module, configured to acquire a temperature value of the power battery when receiving an instruction for charging the power battery; The control module is used for controlling the heater of the power battery to heat the power battery and controlling the charging device to charge the power battery without current when determining that the power battery is currently in a no-current charging state according to the temperature value of the power battery.

8. An electric vehicle, characterized in that: A charging device for a power battery comprising the power battery as claimed in claim 7.

Images