Vehicle battery overcharge prevention system and method

Abstract

The present invention relates to a battery overcharge prevention method, the method including: an overcharged battery power consumption step for detecting overcharge by checking a state of charge of a battery during charging of the battery and consuming power of the overcharged battery; a normal power output step for outputting normal power again when the state of charge becomes equal to or lower than a predetermined state of charge due to the battery power consumption, wherein the power output step and the normal power output step are repeated based on the state of charge of the battery.

Description

Technical Field

[0001] The present invention relates to a method for preventing overcharging of a vehicle battery, and more particularly, to a method for preventing overcharging of a battery used in a vehicle equipped with an E-PTO. Background Art

[0002] Recently, as regulations related to automobile exhaust gases are being strengthened due to environmental pollution, the demand for environmentally friendly vehicles is increasing, and for this reason, research and development of electric vehicles that obtain power by driving a motor using electric energy supplied by a battery after receiving electric energy from the outside and charging the battery is being actively carried out.

[0003] Since a plurality of rechargeable batteries that can be charged and discharged are formed in one pack and the batteries must be charged from an external charger, the battery of such an electric vehicle has a large influence on the mileage of the electric vehicle according to the capacity and charge state of the battery.

[0004] In addition, an electric vehicle equipped with auxiliary equipment and external equipment performing special purposes such as refrigeration equipment or lifting equipment while using electricity as a motive force constitutes an electric power take-off device (E-PTO) that supplies electric power to these auxiliary equipment and external equipment.

[0005] In a method of receiving electric energy from an external charger to a battery and an E-PTO, in the case of a system in which the power required for the E-PTO is received from both the charger and the battery, if the charger and the electric vehicle are continuously connected even after the battery of the electric vehicle is fully charged, the power not consumed by the E-PTO may overcharge the battery.

[0006] Therefore, in the prior art, overcharging is prevented by receiving the necessary power consumed in the E-PTO from the electric vehicle's battery. However, this is because, when the electric vehicle is parked for a long time with a fully charged battery, the battery is not fully charged at the time of departure due to power supply from the battery to the E-PTO, resulting in a disadvantage in that the charging efficiency of the electric vehicle is reduced.

[0007] The basic technology of the present invention is disclosed in the following patent documents.

[0008] [Prior art literature]

[0009] [Patent Document]

[0010] (Patent Document 1) KR1490958 B1

[0011] (Patent Document 2) KR2019-0062824A

[0012] (Patent Document 3) JP4831179 B2

[0013] (Patent Document 4) KR1610507 B1 Summary of the Invention

[0014] Technical issues

[0015] An object of the present invention is to provide a control system and method for improving the efficiency of a battery in a fully charged state and preventing overcharging in an electric vehicle equipped with an E-PTO.

[0016] Technical Solution

[0017] An overcharge prevention method according to an embodiment of the present invention includes: an overcharge detection step for detecting overcharge of a battery; a reduction output power calculation step for calculating an average input power input to the battery in an overcharge state of the battery, and calculating the power that the charger is to reduce output based on the calculated average input power; a charging power reduction request step for requesting a reduction in charging power from the charger based on the calculated reduction output power; a charging power output reduction step in which the charger, having received the charging power reduction request, outputs reduced charging power; an overcharge battery power consumption step in which the reduced charging power output in the charging power output reduction step is input only to an E-PTO, and insufficient power of the E-PTO is supplied from the battery to consume the power of the overcharged battery; a normal power output step in which the charger outputs normal power again when the power of the overcharged battery is consumed and the charging state of the battery is not an overcharged state, wherein the charging power output reduction step and the normal power output step are repeated based on the charging state of the battery.

[0018] The overcharge detection step includes: a charge state checking step for confirming an overcharge state of the battery; and an overcharge current input detection step for detecting and measuring an overcharge current input to the battery when overcharge of the battery is confirmed.

[0019] The reduced output power calculation step includes: an input power calculation step for calculating overcharge power using the detected overcharge current input value; an average input power calculation step for calculating the average input power using the calculated overcharge power and a detection time of the overcharge current input; and a reduced output power calculation step for calculating a reduced output power request to the charger based on the calculated average input power, wherein the reduced output power is power greater than the average input power. The reduced charging power can be obtained by subtracting twice the average input power from the power required for the E-PTO.

[0020] The charging power reduction requesting step includes an output power reduction requesting step of requesting the charger to reduce the output power based on the amount of the reduced power.

[0021] The overcharge state is 101% of the full charge state, and the non-overcharge state is set to 99% or less of the full charge state to keep the battery's charge state close to 100%.

[0022] In a system for preventing overcharging of a battery of an electric vehicle, the battery is configured to supply power to a drive motor and an E-PTO of the electric vehicle, the electric vehicle including: a battery configured to store electric energy supplied from a charger; a motor driven by receiving electric energy from the battery; an E-PTO configured to receive electric energy from the charger or the battery and supply power to electronic devices that perform functions other than driving; and an overcharge control unit configured to control power input to the battery and the E-PTO and power output from the charger, wherein the overcharge control unit includes: a charging state detection unit configured to check the charging state of the battery; a current detection unit configured to detect an input current applied to the battery when the battery is overcharged; a power calculation unit configured to calculate input power based on the input current, calculate an average input power using the input power and a detection time, and calculate an amount of power reduction by which the charger needs to reduce the charging power based on the average input power; and a power reduction request unit configured to request the calculated amount of power reduction from the charger.

[0023] The overcharge control unit is a component of a battery management system (BMS) designed integrally with the battery, or a component of a vehicle control unit (VCU).

[0024] The amount of reduced power to be outputted calculated by the power calculation unit is calculated by subtracting twice the average input power from the power required by the E-PTO.

[0025] Beneficial effects

[0026] According to an embodiment of the present invention, by arranging an overcharge control unit including a charge state detection unit, a current detection unit, a power calculation unit, and a power reduction request unit within the VCU, when the battery is overcharged, the electric vehicle detects the input current, calculates the average input power, and, based on the calculated result, requests the charger to reduce the output power. Consequently, by limiting the power supplied to the electric vehicle from the external charger via the VCU, the overcharged battery can temporarily receive the power required for E-PTO from both the external charger and the battery. Specifically, the VCU controls the charger's output power so that when the battery is overcharged, the battery supplies a portion of the requested power required for E-PTO. By consuming the power of the overcharged battery, the battery can be prevented from overcharging, and battery charging efficiency can be improved compared to the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a block diagram for explaining the configuration of the overall system of the present invention according to an embodiment of the present invention.

[0028] Figure 2 is a flowchart schematically illustrating a method for preventing overcharging of a battery according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms. The embodiments of the present invention are provided only to complete the disclosure of the present invention and to fully inform those skilled in the art of the scope of the present invention. To illustrate the embodiments of the present invention, the drawings may be exaggerated, parts not relevant to the description may be omitted from the drawings, and the same reference numerals in the drawings refer to the same elements.

[0030] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0031] Reference Figure 1 , the present invention includes: an electric vehicle 200 , which includes a vehicle control unit (VCU), an E-PTO and a battery; and a charger 100 for supplying electric energy to the electric vehicle 200 .

[0032] 1. Configuration of the Electric Vehicle of the Present Invention

[0033] A.Battery

[0034] The battery 240 stores electric energy received from the external charger 100 and supplies the stored electric energy to the motor 241 when driving. The battery 240 of the present invention is used to supply electric energy not only to the driving motor 241 but also to the E-PTO 230.

[0035] B. Motor

[0036] The motor 241 receives electric energy from the battery 240 and outputs the received electric energy as driving power of the electric vehicle 200 .

[0037] CE-PTO

[0038] The E-PTO 230 receives electric energy from the external charger 100 or the battery 240 and outputs power required to drive external electronic devices of the electric vehicle 200 .

[0039] D.Electronic equipment

[0040] The electronic equipment 231 is mounted on the electric vehicle 200 and receives power output from the E-PTO 230 to perform functions other than driving, and includes, for example, various electronic equipment 231 such as a refrigerator for refrigerating a tower vehicle, a water pump for fire fighting, a driving device for opening and closing a wing body, and a lifting device for aerial work.

[0041] E.VCU

[0042] The vehicle control unit (VCU) 210 controls the power among the charger 100, the battery 240 in the electric vehicle 200, and the E-PTO 230, calculates the power input in a predetermined unit time supplied to the battery 240 in an overcharged state and the input power to be reduced based on the calculated power through the overcharge control unit 220, and transmits it to the charger 100 to request a reduction in charging power.

[0043] (1) Overcharge control unit

[0044] The overcharge control unit 220 is configured to include a charge state detection unit 221 , a current detection unit 222 , a power calculation unit 223 , and a power reduction request unit 224 , and may be a component of a battery management system (BMS) designed integrally with the battery 240 , or a component of the VCU 210 .

[0045] (2) Charging status detection unit

[0046] The charge state detection unit 221 detects an overcharge state of the battery 240 by checking the charge state of the battery 240, ie, the SOC of the battery 240 in real time. The overcharge state of the battery 240 is determined to exceed a predetermined SOC upper limit value, for example, 101%.

[0047] The upper limit SOC value of the battery 240 may be set differently according to system requirements, and for example, an SOC exceeding 100% of the full charge SOC of the battery 240 may be set as the upper limit of the charge capacity. The lower limit charge capacity may be set to less than 100%.

[0048] (3) Current detection unit

[0049] The current detection unit 222 detects the current value input to the battery 240 even when the battery 240 is in a fully charged state, ie, when the SOC measurement value of the battery 240 is greater than or equal to a predetermined reference value, for example, greater than or equal to 101%.

[0050] The detected input current value is a current that continues to flow into the battery 240 even if the battery 240 is above a predetermined reference SOC value, so it is determined to be an overcharge current, and the input current value for a predetermined time period is detected in order to calculate the input overcharge amount, and at this time, the voltage applied to the battery 240 is measured together and sent to the power calculation unit 223.

[0051] (4) Power calculation unit

[0052] The power calculation unit 223 calculates the average input power detected over a predetermined period of time, i.e., the amount of overcharge power, by using the overcharge input current and the voltage at that time input to the overcharged battery 240. Furthermore, the power reduction request to the charger 100 is calculated based on the calculated average input power.

[0053] At this point, even if the SOC of battery 240 is, for example, 101% or more, battery 240 is still in an overcharged state due to the excessive power input over a predetermined period of time. To restore battery 240 to a normal state, the overcharged power of battery 240 must be consumed. In the present invention, the power output from charger 100 is distributed and supplied to E-PTO 230 and battery 240. As a method for consuming the power of battery 240, E-PTO 230 requests a reduction in the charging power output from charger 100, thereby requesting the charger to output power less than the required power. Consequently, the entire reduced charging power output, which is less than the required power of E-PTO 230, is supplied to E-PTO 230. Furthermore, the shortfall in the required power of E-PTO 230 is input from battery 240 and supplied to E-PTO 230, causing the overcharged battery 240 to consume power.

[0054] On the other hand, the reduced charging power requested of the charger 100 can be calculated by subtracting a larger power from the required power of the E-PTO 230, rather than simply the overcharge power, which is the average input power to the overcharged battery 240, as the reduced output power. For example, the reduced charging power requested of the charger can be calculated as the power obtained by subtracting twice the average input power (overcharge power) of the overcharged battery 240 from the required power of the E-PTO 230. Depending on system requirements, a reduction in power obtained by subtracting 1 or more power rather than a multiple of 2 can be requested.

[0055] (5) Power reduction request unit

[0056] The power reduction request unit 224 sends a request signal to the charger 100 to output the reduced charging power reduced by the calculated reduced output power. In addition, when the SOC of the battery 240 detected by the charge state detection unit 221 is detected to be less than or equal to a predetermined value, such as 99%, the output reduction request is stopped and normal charging is requested.

[0057] F. Charger

[0058] The charger 100 is connected to the electric vehicle 200 and receives a request for reduced output or normal output according to the SOC state of the battery 240 detected by the overcharge control unit 220 of the VCU 210, and outputs reduced output or normal output. For example, when the SOC is 101% or more, the reduced charging power is output to reduce the calculated reduced output power to prevent overcharging, and when the SOC is 99% or less, normal power is output, and the battery 240 SOC can be maintained close to 100%.

[0059] 2. Method for preventing overcharging of a battery of an electric vehicle according to the present invention

[0060] Figure 2 is a flowchart illustrating a method for preventing overcharging of the battery 240 of the electric vehicle 200 according to an embodiment of the present invention.

[0061] Each process is described below.

[0062] A. Overcharge Detection Step S10

[0063] First, the battery 240 is charged by connecting the charger 100 and the electric vehicle 200 .

[0064] The overcharge detection step is a process for detecting a state in which the battery is overcharged and continuously detecting a charging current flowing into the battery in the overcharge state.

[0065] This may be configured to include an overcharge state checking step and an overcharge current input detecting step.

[0066] (1) Overcharge status check steps

[0067] During charging, the current detection unit 222 of the overcharge control unit 220 checks the charging state of the battery 240 , ie, the SOC of the battery 240 , in real time to confirm the charging state.

[0068] As a result of checking the state of charge, if the SOC is greater than a predetermined SOC upper limit value, for example, 101% or more, the state of charge is determined to be an overcharge state.

[0069] (2) Overcharge current input detection steps

[0070] The overcharge current input detection step is a step of detecting and measuring an overcharge current input in which a charging current is continuously input to the battery even in the overcharge state as a result of the check in the overcharge state check step.

[0071] When the SOC of battery 240 exceeds a predetermined upper limit value, for example, 101% or more, current detection unit 222 detects the current input to battery 240 at this time. Since the detected input current value is a current that continues to flow into battery 240 even when battery 240 is above a predetermined reference SOC, it is determined to be an overcharge current. In order to calculate the input amount of overcharge power, the input current value is detected for a predetermined period of time, and at this time, the voltage applied to battery 240 is also measured and sent to power calculation unit 223.

[0072] The upper limit SOC value of the battery 240 may be set differently according to system requirements, and for example, an SOC exceeding 100% of the full charge SOC of the battery 240 may be set as the upper limit charge capacity. The lower limit charge capacity may be set to less than 100%.

[0073] B. Reduce output power calculation step S20

[0074] The overcharge input current and voltage measured at this time are used to calculate the average input power during the detected predetermined period, i.e., the amount of overcharge power. Furthermore, the output power reduction (power cutoff amount) requested from the charger 100 is calculated based on the calculated average input power.

[0075] At this time, even though the SOC of battery 240 is 100%, battery 240 is still in an overcharged state due to excessive power input over a predetermined period of time. Therefore, in order to restore the battery to a normal state, the overcharge power of battery 240 must be consumed. The power output from charger 100 is distributed and supplied to E-PTO 230 and battery 240, and as a method of consuming the power of battery 240, the power output from charger 100 is output at a power level less than the power required by E-PTO 230. Therefore, the power output from charger 100 is distributed and supplied to E-PTO 230 and battery 240, and as a method of consuming the power of battery 240, the power output from charger 100 is output at a power level less than the power required by E-PTO 230.

[0076] Therefore, the charging power reduction requested from the charger 100 is calculated by subtracting a larger power from the required power of the E-PTO 230, not just the average input power of the overcharged battery 240, as the output power reduction. For example, the charging power reduction requested from the charger can be calculated by subtracting twice the average input power of the battery 240 from the required power of the E-PTO 230. Depending on system requirements, a reduction of 1 or more times, rather than 2 or more times, can be requested.

[0077] C. Charging Power Reduction Request Step S30

[0078] The power reduction request unit 224 requests the charger 100 to output a reduced charging power obtained by reducing the calculated reduced output power from the required power of the E-PTO 230. In addition, when the SOC of the battery 240 detected by the charge state detection unit 221 is detected as a predetermined lower limit value, for example, 99% or less, the request for the charging power reduction may be stopped and normal charging may be requested.

[0079] D. Reducing charging power output step S40

[0080] The charger 100 outputs the reduced charging power requested by the power reduction request unit 224. In addition, when the SOC of the battery 240 detected by the charge state detection unit 221 is detected as a predetermined lower limit value, for example, 99% or less, normal power can be output by interrupting the charging power reduction request.

[0081] E. Overcharge Battery Power Consumption Step S50

[0082] The reduced power input from the charger 100 that has received the charging power reduction request to the electric vehicle 200 is input only to the E-PTO 230 in accordance with the power required by the E-PTO 230. Therefore, since the battery 240 is no longer overcharged and the charger 100 does not transmit all the power required by the E-PTO 230, insufficient power is supplied from the battery 240 to the E-PTO 230, and thus, the overcharged battery consumes power to escape the overcharged state.

[0083] F. Normal Power Charging Step S60

[0084] If the charging power output reduction step continues in the overcharged state of the battery 240, the SOC decreases due to power consumption of the battery 240, and when the SOC of the battery 240 is confirmed to be a predetermined lower limit value, for example, 99% or less, normal charging is performed by stopping the charging power reduction request transmitted from the VCU 210 to the charger 100.

[0085] The system and charging method of the present invention periodically repeat the above process according to the state of charge of the battery 240. Therefore, the battery 240 can be prevented from overcharging by maintaining a predetermined lower limit value or upper limit value, such as 99% to 101% SOC state, and will remain close to the fully charged state.

[0086] The above embodiments of the present invention are intended to illustrate the present invention and are not intended to limit the present invention. It should be noted that the configurations and methods disclosed in the above embodiments of the present invention can be combined and modified in various forms by combining or intersecting with each other, and their modifications can also be considered to be within the scope of the present invention. That is, the present invention will be implemented in various different forms within the scope of the claims and equivalent technical spirit, and those skilled in the art to which the present invention belongs will understand that various embodiments are feasible within the scope of the technical spirit of the present invention.

[0087] The description of the reference numerals in the drawings of the present invention is as follows.

[0088] 100: Charger

[0089] 200: Electric vehicles

[0090] 210: VCU

[0091] 220: Overcharge control unit

[0092] 221: Charging status detection unit

[0093] 222: Current detection unit

[0094] 223: Power calculation unit

[0095] 224: Power reduction request unit

[0096] 230: Power output device

[0097] 231: Electronic equipment

[0098] 240: Battery

[0099] 241: Motor

Claims

1. A method for preventing overcharging of a battery of an electric vehicle, the battery being configured to supply power to a drive motor and an E-PTO of the electric vehicle, the method comprising: an overcharge detection step for detecting overcharge of the battery, comprising: a charge state checking step for confirming an overcharge state of the battery; and an overcharge current input detection step for detecting and measuring an overcharge current input to the battery when overcharge of the battery is confirmed; The output power reduction calculation step, for calculating the power to be reduced from the output of the charger based on the average input power of the battery, comprises: an input power calculation step for calculating overcharge power using the detected overcharge current input value; an average input power calculation step of calculating the average input power using the calculated overcharge power and a detection time of the overcharge current input; and a reduced output power calculation step of calculating a reduced output power to be requested from the charger based on the calculated average input power; and A charging power reduction requesting step is for requesting a reduction in charging power from the charger based on the calculated reduced output power.

2. The method according to claim 1, further comprising: a charging power output reducing step, in which the charger that has received the charging power reduction request outputs reduced charging power; an overcharged battery power consumption step in which the reduced charging power output in the reduced charging power output step is input only to the E-PTO, and insufficient power of the E-PTO is supplied from the battery to consume power of the overcharged battery; a normal power output step in which the charger outputs normal power again when the power of the overcharged battery is consumed and the charge state of the battery is not an overcharged state, The step of reducing the charging power output and the step of outputting the normal power are repeated based on the battery charging state.

3. The method according to claim 1, wherein The reduced output power is power greater than the average input power.

4. The method according to claim 1, wherein The charging power reduction requesting step includes requesting the charger to output reduced charging power obtained by subtracting the calculated reduced output power from the required power of the E-PTO.

5. The method according to claim 1, wherein The overcharge state is 101% of a full charge state, and the non-overcharge state is set to 99% or less of a full charge state to maintain the charge state of the battery close to 100%.

6. A system for preventing overcharging of a battery of an electric vehicle, the battery being configured to supply power to a drive motor and an E-PTO of the electric vehicle, in, The electric vehicle comprises: a battery configured to store electrical energy supplied from the charger; a motor driven by receiving electric energy from the battery; An E-PTO configured to receive electric energy from the charger or the battery and supply power to an electronic device that performs a function other than driving; and an overcharge control unit configured to control power input to the battery and the E-PTO and power output from the charger, Wherein, the overcharge control unit includes: a charging state detection unit configured to check a charging state of the battery; a current detection unit configured to detect an input current applied to the battery when the battery is overcharged; a power calculation unit configured to calculate input power based on the input current, calculate average input power using the input power and a detection time, and calculate an amount of power reduction by which the charger needs to reduce charging power based on the average input power; and The power reduction request unit is configured to request the charger to output reduced charging power obtained by subtracting the calculated amount of reduced power from the power required by the E-PTO.

7. The system according to claim 6, wherein: The overcharge control unit is a component of a battery management system (BMS) designed integrally with a battery, or a component of a vehicle control unit (VCU).

8. The system according to claim 6, wherein: The amount of reduced power calculated by the power calculation unit is an amount of power greater than the average input power.

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