A new energy vehicle battery automatic charging method and system

Abstract

A new energy vehicle battery automatic charging method, comprising step S1: STM32CPU main control chip real-time parameter acquisition; step S2: before the start of the i-th stage of the charging process, the state of charge SOC is updated; step S3: when the current state of charge SOC is lower than Sm, Sm is the minimum power of the charging cycle, and the current is C / 10; step S4: when the current state of charge SOC is between Sm and St, the charging current I i :Step S5: If the current SOC is greater than St, end the charging process; Step S6: Repeat steps S2 to S5 until charging is completed. The present invention adjusts the initial power Si of the process and sets the weight of the power at the end of the expected charging, so that the current is in the expected current state, and the battery can be quickly charged to reduce the loss.

Description

Technical Field

[0001] The present invention relates to the field of new energy vehicles, and in particular to a method and system for automatically charging a battery of a new energy vehicle. Background Art

[0002] At present, with the development of technology, the use of new energy vehicles is becoming more and more popular, and the application of new energy vehicle batteries is becoming more and more extensive. Lithium-ion power batteries have the advantages of high specific energy, long cycle life, and low self-discharge rate, and have become the main energy source for electric vehicles. Since the characteristics of lithium-ion batteries are closely related to the operating temperature, when the lithium-ion battery is charged and discharged; the battery management system will limit the charge and discharge current according to the current temperature and capacity to ensure that no damage is caused to the battery. The heat generated inside the battery includes reaction heat, Joule heat, polarization heat and side reaction heat. For lithium-ion batteries, the normal operating temperature range of the battery is 20-60℃, and the heat generated by lithium-ion batteries mainly includes Joule heat and polarization heat. Joule heat and polarization heat are caused by the ohmic internal resistance and polarization internal resistance of the battery respectively. Ohmic internal resistance is composed of electrode materials, electrolytes, diaphragm resistance and contact resistance of various parts; polarization internal resistance refers to the resistance caused by polarization during electrochemical reactions, including electrochemical polarization and concentration polarization.

[0003] High current charging can shorten the charging time, but it will increase the polarization voltage and increase more energy loss; low current charging will prolong the charging time, but it can reduce the polarization voltage and keep the energy loss at a low level. In order to keep the battery stable and healthy for a long time, the current needs to be adjusted. During the charging and discharging process, the internal resistance and power of the battery change. Different internal resistances and charging powers lead to different losses. How to achieve less loss has been studied in the prior art. However, most of the existing battery charging uses a fixed current or fixed voltage without considering the loss, or does not accurately reduce the loss, resulting in more loss during the charging process, more heat generated, and reduced vehicle life. In addition, the prior art does not take into account the impact of battery power on the loss during the charging process, and does not automatically adjust the current according to the expected charging value. Therefore, reducing charging losses and enhancing heat dissipation have become urgent needs. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a new energy vehicle battery automatic charging method and system. The new energy vehicle battery automatic charging method and system of the present invention significantly improve the charging accuracy and automation level, so that the use efficiency and convenience of new energy vehicles are greatly improved, and the user experience is enhanced; a new energy vehicle battery automatic charging method, comprising:

[0005] Step S1: The STM32CPU main control chip collects the open circuit voltage and initial power Si of the battery before charging begins in real time, sets the expected power at the end of charging to St and the expected charging time T, and divides the charging process into N stages, with equal charging power in each stage;

[0006] Step S2: updating the state of charge SOC before the start of the i-th stage of the charging process;

[0007] Step S3: When the current state of charge SOC is lower than Sm, Sm is the minimum charge of the charging cycle, and the current is C / 10;

[0008] Step S4: When the current state of charge SOC is between Sm and St, the current I in the i-th stage of the charging process i for:

[0009]

[0010] Among them, T CC represents the charging time under constant current state with a charging cycle of 25%-95% SOC, R(SOC) is the total internal resistance of the battery, R i is the equivalent internal resistance of the battery in the i-th charging stage, C 0 is the total capacity of the battery, δ is the adaptive coefficient value;

[0011] Step S5: If the current SOC is greater than St, the charging process ends;

[0012] Step S6: Repeat steps S2 to S5 until charging is completed.

[0013] Preferably, the R(SOC) is the total internal resistance of the battery, which is composed of the sum of the ohmic resistance and the polarization resistance.

[0014] Preferably, the STM32CPU main control chip is electrically connected to the intelligent gateway, the intelligent gateway is composed of a main board, a wireless board and an interface board, the main board is composed of an FPGA chip; the interface board supports four serial interfaces, including RS232, RS485, RS422 and an analog sampling interface.

[0015] Preferably, R(SOC) is the total internal resistance of the battery, R i is the equivalent internal resistance of the battery in the i-th charging stage, R(SOC) and R i A two-dimensional table based on SOC, temperature and internal resistance is established through experiments, and the data between the test points are obtained through two-dimensional linear interpolation.

[0016] Preferably, the STM32CPU main control chip also includes real-time collection of charging voltage and current values ​​and automatic adjustment of charging voltage and current values ​​based on a variable universe fuzzy control scheme, stops the charging process when charging is completed, and displays charging completion on a display screen.

[0017] The present application also provides a new energy vehicle battery automatic charging system, comprising:

[0018] Parameter detection module: The STM32CPU main control chip collects the open circuit voltage and initial power Si of the battery before charging starts in real time, sets the expected power at the end of charging to St and the expected charging time T, and divides the charging process into N stages, with equal charging power in each stage;

[0019] State of charge update module: updates the state of charge SOC before the start of the i-th stage of the charging process;

[0020] Current size selection module 1: When the current state of charge SOC is lower than Sm, Sm is the minimum power of the charging cycle, and the current is C / 10;

[0021] Current size selection module 2: When the current state of charge SOC is between Sm and St, the current I in the i-th section of the charging process i for:

[0022]

[0023] Among them, T CC represents the charging time under constant current state with a charging cycle of 25%-95% SOC, R(SOC) is the total internal resistance of the battery, R i is the equivalent internal resistance of the battery in the i-th charging stage, C 0 is the total capacity of the battery, δ is the adaptive coefficient value;

[0024] Current size selection module 3: If the current SOC is greater than St, the charging process ends;

[0025] Display module: Repeat step S2 to step S5 until charging is completed, and display charging completion on the LCD display.

[0026] Preferably, the R(SOC) is the total internal resistance of the battery, which is composed of the sum of the ohmic resistance and the polarization resistance.

[0027] Preferably, the STM32CPU main control chip is electrically connected to the intelligent gateway, the intelligent gateway is composed of a main board, a wireless board and an interface board, the main board is composed of an FPGA chip; the interface board supports four serial interfaces, including RS232, RS485, RS422 and an analog sampling interface.

[0028] Preferably, R(SOC) is the total internal resistance of the battery, R i is the equivalent internal resistance of the battery in the i-th charging stage, R(SOC) and R i A two-dimensional table based on SOC, temperature and internal resistance is established through experiments, and the data between the test points are obtained through two-dimensional linear interpolation.

[0029] Preferably, the STM32CPU main control chip also includes real-time collection of charging voltage and current values ​​and automatic adjustment of charging voltage and current values ​​based on a variable universe fuzzy control scheme, stops the charging process when charging is completed, and displays charging completion on a display screen.

[0030] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0031] The problem that the traditional technology has large losses and cannot be automatically adaptively adjusted is solved. The present application creatively adjusts the charging power under different charge states by adjusting δ as the adaptive coefficient value and combining the initial power Si, setting the power at the end of the expected charging as St-Sm, so as to reduce the loss and the heat generated by the battery charging, thereby greatly enhancing the battery life and reducing the loss; δ is the adaptive coefficient value, and the weight of the initial power Si and the power at the end of the expected charging are adjusted so that the current can be quickly charged to reduce the loss according to the expected current state. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a system diagram of a new energy vehicle battery automatic charging method of the present invention; DETAILED DESCRIPTION

[0033] Those skilled in the art understand that, as mentioned in the background art, in the traditional technology, the internal resistance and power of the battery change during the charging and discharging process. Different internal resistances and charging powers cause different losses. How to achieve less loss has been studied in the prior art. However, most of the existing battery charging uses a fixed current or a fixed voltage without considering the loss, or does not accurately reduce the loss, resulting in more loss during the charging process, more heat generated, and reduced vehicle life. In addition, the prior art does not consider the impact of the battery power on the loss during the charging process, and does not automatically adjust the current according to the expected charging value. Therefore, reducing charging losses and enhancing heat dissipation have become urgent needs. In order to make the above-mentioned purposes, features and beneficial effects of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0034] Embodiment 1:

[0035] Figure 1 A system diagram of a new energy vehicle battery automatic charging method of the present application is shown. In some embodiments, a new energy vehicle battery automatic charging method includes:

[0036] Step S1: The STM32CPU main control chip collects the open circuit voltage and initial power Si of the battery before charging begins in real time, sets the expected power at the end of charging to St and the expected charging time T, and divides the charging process into N stages, with the charging power of each stage being equal; under the condition that the charging time is not extended and the charged power is not reduced, by optimizing the current value of each stage, the current combination with the smallest charging loss is selected as the optimal current;

[0037] Step S2: updating the state of charge SOC before the start of the i-th stage of the charging process;

[0038] Step S3: When the current state of charge SOC is lower than Sm, Sm is the minimum charge of the charging cycle, and the current is C / 10;

[0039] Step S4: When the current state of charge SOC is between Sm and St, the current I in the i-th stage of the charging process i for:

[0040]

[0041] Among them, T CC represents the charging time under constant current state with a charging cycle of 25%-95% SOC, R(SOC) is the total internal resistance of the battery, R i is the equivalent internal resistance of the battery in the i-th charging stage, C 0 is the total capacity of the battery, δ is the adaptive coefficient value;

[0042] Step S5: If the current SOC is greater than St, the charging process ends;

[0043] Step S6: Repeat steps S2 to S5 until charging is completed.

[0044] In some embodiments, the R(SOC) is the total internal resistance of the battery, which is composed of the sum of the ohmic resistance and the polarization resistance.

[0045] In some embodiments, the STM32CPU main control chip is electrically connected to the intelligent gateway, the intelligent gateway is composed of a main board, a wireless board and an interface board, the main board is composed of an FPGA chip; the interface board supports four serial interfaces, including RS232, RS485, RS422 and an analog sampling interface.

[0046] In some embodiments, R(SOC) is the total internal resistance of the battery, R i is the equivalent internal resistance of the battery in the i-th charging stage, R(SOC) and R i A two-dimensional table based on SOC, temperature and internal resistance is established through experiments, and the data between the test points are obtained through two-dimensional linear interpolation.

[0047] The following table shows the relationship between resistance and electric quantity, where the unit of resistance is ohm:

[0048]

[0049] In some embodiments, the STM32CPU main control chip also includes real-time collection of charging voltage and current values ​​and automatic adjustment of charging voltage and current values ​​based on a variable domain fuzzy control scheme. When charging is completed, the charging process is stopped and the charging completion is displayed on the display screen.

[0050] Embodiment 2:

[0051] The present application also provides a new energy vehicle battery automatic charging system, comprising:

[0052] Parameter detection module: The STM32CPU main control chip collects the open circuit voltage and initial power Si of the battery before charging starts in real time, sets the expected power at the end of charging to St and the expected charging time T, and divides the charging process into N stages, with equal charging power in each stage;

[0053] State of charge update module: updates the state of charge SOC before the start of the i-th stage of the charging process;

[0054] Current size selection module 1: When the current state of charge SOC is lower than Sm, Sm is the minimum power of the charging cycle, and the current is C / 10;

[0055] Current size selection module 2: When the current state of charge SOC is between Sm and St, the current I in the i-th section of the charging process i for:

[0056] Among them, T CC represents the charging time under constant current state with a charging cycle of 25%-95% SOC, R(SOC) is the total internal resistance of the battery, R i is the equivalent internal resistance of the battery in the i-th charging stage, C 0 is the total capacity of the battery, δ is the adaptive coefficient value;

[0057] Current size selection module 3: If the current SOC is greater than St, the charging process ends;

[0058] Display module: Repeat step S2 to step S5 until charging is completed, and display charging completion on the LCD display.

[0059] In some embodiments, the R(SOC) is the total internal resistance of the battery, which is composed of the sum of the ohmic resistance and the polarization resistance.

[0060] In some embodiments, the STM32CPU main control chip is electrically connected to the intelligent gateway, the intelligent gateway is composed of a main board, a wireless board and an interface board, the main board is composed of an FPGA chip; the interface board supports four serial interfaces, including RS232, RS485, RS422 and an analog sampling interface.

[0061] In some embodiments, R(SOC) is the total internal resistance of the battery, R i is the equivalent internal resistance of the battery in the i-th charging stage, R(SOC) and R i A two-dimensional table based on SOC, temperature and internal resistance is established through experiments, and the data between the test points are obtained through two-dimensional linear interpolation.

[0062] In some embodiments, the STM32CPU main control chip also includes real-time collection of charging voltage and current values ​​and automatic adjustment of charging voltage and current values ​​based on a variable domain fuzzy control scheme. When charging is completed, the charging process is stopped and the charging completion is displayed on the display screen.

[0063] The present invention provides a new energy vehicle battery automatic charging method and system, which solves the problem that the traditional technology has large losses and cannot be automatically adaptively adjusted. The present application creatively adjusts the charging power under different charge states by adjusting δ as the adaptive coefficient value and combining the initial power Si, setting the power at the end of the expected charging as St-Sm, so as to reduce the loss and the heat generated by the battery charging, thereby greatly enhancing the battery life and reducing the loss; δ is the adaptive coefficient value, and by adjusting the weight of the initial power Si and the power at the end of the expected charging, the current can quickly realize battery charging according to the current state expected to be achieved.

[0064] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products, and thus the present application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects.

[0065] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A new energy vehicle battery automatic charging method, characterized in that: include: Step S1: The STM32CPU main control chip collects the open circuit voltage and initial power Si of the battery before charging begins in real time, sets the expected power at the end of charging to St and the expected charging time T, and divides the charging process into N stages, with the charging power of each stage being equal; under the condition that the charging time is not extended and the charged power is not reduced, by optimizing the current value of each stage, the current combination with the smallest charging loss is selected as the optimal current; Step S2: updating the state of charge SOC before the start of the i-th stage of the charging process; Step S3: When the current state of charge SOC is lower than Sm, Sm is the minimum charge of the charging cycle, and the current is C / 10; Step S4: When the current state of charge SOC is between Sm and St, the current of the i-th stage of the charging process for: ; in, Represents the charging time under constant current state with a charging cycle of 25%-95% SOC, R (SOC) is the total internal resistance of the battery, is the equivalent internal resistance of the battery in the i-th charging stage, is the total battery capacity, is the adaptive coefficient value; Step S5: If the current SOC is greater than St, the charging process ends; Step S6: Repeat steps S2 to S5 until charging is completed.

2. A new energy vehicle battery automatic charging method according to claim 1, characterized in that: The R (SOC) is the total internal resistance of the battery, which is composed of the sum of the ohmic resistance and the polarization resistance.

3. The automatic charging method for new energy vehicle batteries according to claim 1, characterized in that: The STM32CPU main control chip is electrically connected to the intelligent gateway, which is composed of a main board, a wireless board and an interface board. The main board is composed of an FPGA chip; the interface board supports four serial interfaces, including RS232, RS485, RS422 and an analog sampling interface.

4. The automatic charging method for new energy vehicle batteries according to claim 1, characterized in that: The R(SOC) is the total internal resistance of the battery, is the equivalent internal resistance of the battery in the i-th charging stage, R(SOC) and A two-dimensional table based on SOC, temperature and internal resistance is established through experiments, and the data between the test points are obtained through two-dimensional linear interpolation.

5. The automatic charging method for new energy vehicle batteries according to claim 1, characterized in that: The STM32CPU main control chip also includes real-time collection of charging voltage and current values ​​and automatic adjustment of charging voltage and current values ​​based on a variable universe fuzzy control scheme. When charging is completed, the charging process is stopped and the charging completion is displayed on a display screen.

6. A new energy vehicle battery automatic charging system, characterized in that: include: Parameter detection module: The STM32CPU main control chip collects the open circuit voltage and initial power Si of the battery before charging starts in real time, sets the expected power at the end of charging to St and the expected charging time T, and divides the charging process into N stages, with equal charging power in each stage; State of charge update module: updates the state of charge SOC before the start of the i-th stage of the charging process; Current size selection module 1: When the current state of charge SOC is lower than Sm, Sm is the minimum power of the charging cycle, and the current is C / 10; Current selection module 2: When the current state of charge SOC is between Sm and St, the current of the i-th stage of the charging process for: ; in, Represents the charging time under constant current state with a charging cycle of 25%-95% SOC, R (SOC) is the total internal resistance of the battery, is the equivalent internal resistance of the battery in the i-th charging stage, is the total battery capacity, is the adaptive coefficient value; Current size selection module 3: If the current SOC is greater than St, the charging process ends; Display module: repeating step S2 to step S5 until charging is completed, and displaying charging completion on the LCD display; Under the conditions that the charging time is not extended and the charged amount is not reduced, the current value of each stage is optimized and the current combination with the smallest charging loss is selected as the optimal current.

7. The automatic charging system for new energy vehicle batteries according to claim 6 is characterized in that: The R (SOC) is the total internal resistance of the battery, which is composed of the sum of the ohmic resistance and the polarization resistance.

8. The automatic charging system for new energy vehicle batteries according to claim 6 is characterized in that: The STM32CPU main control chip is electrically connected to the intelligent gateway, which is composed of a main board, a wireless board and an interface board. The main board is composed of an FPGA chip; the interface board supports four serial interfaces, including RS232, RS485, RS422 and an analog sampling interface.

9. The automatic charging system for new energy vehicle batteries according to claim 6, characterized in that: The R(SOC) is the total internal resistance of the battery, is the equivalent internal resistance of the battery in the i-th charging stage, R(SOC) and A two-dimensional table based on SOC, temperature and internal resistance is established through experiments, and the data between the test points are obtained through two-dimensional linear interpolation.

10. The automatic charging system for new energy vehicle batteries according to claim 6, characterized in that: The STM32CPU main control chip also includes real-time collection of charging voltage and current values ​​and automatic adjustment of charging voltage and current values ​​based on a variable universe fuzzy control scheme. When charging is completed, the charging process is stopped and the charging completion is displayed on a display screen.

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