Sodium-lithium battery car and charging control method

Abstract

The application provides a sodium-lithium battery car and a charging control method. The sodium-lithium battery car is designed as a cross arrangement, a voltage and current adjusting array is arranged, the internal and external temperatures of the battery are considered, a charging characteristic map for charging strategy control is constructed, and the characteristics of each cell string are considered to control the charging of the battery car to prevent the battery from catching fire due to too fast and high temperature rise during charging. Meanwhile, when the battery car is not used for a long time, the battery car battery is repeatedly charged and naturally discharged between 20% and 90% of the power to ensure that the battery car battery is neither damaged due to battery depletion nor worn out due to repeated charging and reduced cycle times, and convenience is provided for users.

Description

Technical Field

[0001] The present invention relates to an electric battery vehicle and a charging control method, and in particular to an electric battery vehicle using a sodium-lithium hybrid energy storage battery and a charging control method thereof. Background Art

[0002] Electric bikes are now ubiquitous in every household, but existing models often catch fire during charging due to varying quality, design flaws, or improper use, posing significant safety risks and financial losses to users. A significant proportion of these fires are caused by battery damage, aging, or improper charging strategies. Furthermore, if an electric bike's battery is left unused for extended periods, its charge will naturally deplete. Failure to recharge the battery promptly can also damage the battery. Furthermore, if the battery is temporarily used after being stored for an extended period, it may even run out of power. Therefore, a sodium-lithium electric bike charging control method is urgently needed to address these issues. Summary of the Invention

[0003] The purpose of the present invention is to provide a sodium-lithium battery vehicle charging control method for reducing the problems of spontaneous combustion during charging and battery loss and facilitating users to use the battery vehicle at any time. The charging control steps are as follows:

[0004] S1: When the power signal detection module detects that the mains input terminal is connected to the power supply, the control board is awakened. The processor controls the voltage and current adjustment array through the register to charge the battery string according to the charging strategy and the characteristic data of the battery to be charged. At the same time, the timer is notified to count the power supply connection time.

[0005] S2: The temperature sensor detects the external ambient temperature and internal temperature of the battery pack. The processor adjusts the charging current of the entire battery pack according to the external ambient temperature of the battery pack and the difference between the internal temperature of the battery pack and the upper temperature threshold. The adjustment rules are as follows:

[0006] (1) When the external ambient temperature of the battery pack exceeds the threshold value T1, it is determined whether the current total charging current of the battery pack is greater than the threshold value A1. If it is greater than the threshold value A1, the total charging current is reduced to the threshold value A1. If it is not greater than the threshold value A1, no adjustment is made.

[0007] (2) When the difference between the internal temperature of the battery pack and the upper temperature threshold is less than a certain value, the total charging current of the current battery pack is reduced until the battery pack no longer heats up.

[0008] (3) Charging stops when it is detected that the internal temperature of the battery pack reaches the upper threshold.

[0009] S3: The voltage and current detection unit continuously detects the voltage and current at both ends of the charging cell string and stores the detected voltage and current data in the memory. When it is detected that the cell string is fully charged, the processor controls the AC-DC module and the voltage and current adjustment array to stop working, and charging is completed.

[0010] S4: The processor periodically obtains the charging voltage and current data at both ends of the battery string from the memory, uses the capacity loss analysis model to analyze the capacity loss degree of each battery string, corrects the charging capacity, full charge voltage, and battery string charging voltage and current limit data of each battery string, and updates the charging characteristic map.

[0011] After step S3, the following charging control steps are performed:

[0012] SS1: When the battery vehicle is fully charged, the power signal detection module monitors whether the AC input terminal is disconnected from the power supply. When the power supply is disconnected, the timer is cleared and the control board is put into sleep mode to reduce power loss. The process goes to step S1. When the power signal detection module monitors that the power supply is not disconnected, the process goes to step SS2.

[0013] SS2: Determine whether the remaining power of the battery of the electric vehicle is lower than the third threshold; if so, the processor controls the voltage and current adjustment array through the register to charge the battery string according to the charging strategy until the battery power reaches the fourth threshold, the processor controls the AC-DC module and the voltage and current adjustment array to stop working, charging is completed, and go to step SS1; if the remaining power of the battery of the electric vehicle is not lower than the third threshold, go to step SS3.

[0014] SS3: Check once every certain time t1 whether the AC power input terminal is disconnected. When the power is disconnected, clear the timer and put the control board into sleep mode to reduce power loss; go to step S1; when the power signal detection module detects that the power is not disconnected, go to step SS2.

[0015] The present invention also provides a sodium-lithium battery vehicle, which is characterized by:

[0016] The sodium-lithium battery car includes a charging control system and a sodium-lithium hybrid battery cell. The lithium battery cell strings and the sodium battery cell strings are arranged crosswise. Each battery cell string includes multiple battery cells. The battery cell strings are isolated by epoxy resin plates.

[0017] The charging control system includes a control board, which integrates a processor, a mains input terminal, a Bluetooth module, an AC-DC module, a voltage and current adjustment array, a memory, a voltage and current detection module, a temperature sensor, a register, a timer, and a power signal detection module;

[0018] The voltage and current adjustment array is used to adjust the output voltage and current to charge each battery string according to the charging control strategy and the characteristic data of the battery to be charged under the control of the processor;

[0019] The memory is used to store charging control data and historical charging data;

[0020] The charging control data includes charging control strategy data;

[0021] The historical charging data includes a charging voltage and current curve of each battery cell string during each charging.

[0022] The register controls the voltage and current adjustment array to output corresponding voltage and current to the corresponding battery cell string under the control of the processor;

[0023] The temperature sensor includes a first temperature sensor and a second temperature sensor; the first temperature sensor is used to detect the ambient temperature outside the battery pack, and the second temperature sensor is used to detect the internal temperature of the battery pack;

[0024] The timer is used to record the time when the mains input terminal is connected to the power supply;

[0025] The power signal detection module is used to detect whether the mains input terminal is connected to power.

[0026] Beneficial effects: The sodium-lithium battery vehicle of the present invention controls the charging of the battery vehicle by designing the sodium-lithium hybrid battery to be arranged in a cross pattern, setting a voltage and current adjustment array, considering the internal and external temperatures of the battery, and constructing a charging characteristic map for charging strategy control, taking into account the characteristics of each battery string to prevent the battery temperature from rising too quickly and too high during charging and causing spontaneous combustion; at the same time, when the user does not use the battery vehicle for a long time, by controlling the battery vehicle battery to be repeatedly charged and naturally discharged between 20% and 90% of power, it is ensured that the battery vehicle battery will neither be damaged due to battery depletion nor lost due to repeated charging and reducing the number of cycles, which also provides convenience for the user. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a top view of the sodium-lithium battery pack;

[0028] Figure 2 Schematic diagram of the charging control board DETAILED DESCRIPTION

[0029] Example 1: The present invention provides a sodium-lithium battery vehicle, which is used to reduce the problems of spontaneous combustion during charging, battery loss, and facilitate users to use the battery vehicle at any time.

[0030] The sodium-lithium battery car includes a charging control system and a sodium-lithium hybrid battery cell. The sodium-lithium hybrid battery cell structure is as follows: Figure 1As shown, lithium battery cell strings and sodium battery cell strings are arranged crosswise, each battery cell string includes multiple battery cells, and the battery cell strings are isolated by epoxy resin plates;

[0031] The purpose of the cross-arrangement is that sodium batteries are not prone to spontaneous combustion. The use of sodium batteries has the effect of thermal insulation on lithium batteries. At the same time, the high energy density of lithium batteries can be used to maximize the endurance of electric vehicles.

[0032] like Figure 2 As shown, the charging control system includes a control board, which integrates a processor (CPU), a mains input terminal, a Bluetooth module, an AC-DC module, a voltage and current adjustment array, a memory, a voltage and current detection module, a temperature sensor, a register, a timer, and a power signal detection module;

[0033] The processor (CPU) is used to control the charging system to charge the sodium-lithium battery. The processor is connected to the mobile phone through the Bluetooth module.

[0034] The mains power input and output terminals are used to connect to the mains power to charge the battery vehicle;

[0035] The Bluetooth module is used to connect and communicate with the Bluetooth module of the mobile phone. The Bluetooth module is provided with a manual switch, and the user manually turns on the Bluetooth module when in use;

[0036] The AC-DC module is an AC-DC conversion unit;

[0037] The AC-DC conversion unit is used to convert AC power into DC power;

[0038] The voltage and current adjustment array is used to adjust the output voltage and current to charge each battery string under the control of the processor according to the charging control strategy and the characteristic data of the battery to be charged; the specific implementation is as follows: the voltage and current adjustment array includes N voltage and current adjustment units, N is a positive integer, M is an integer multiple of N, and M is the number of battery strings contained in the battery; the user can set the number of N as needed. For example, if the user wants to increase the charging speed, N=M can be set. In this way, each voltage and current adjustment unit corresponds to a battery string. Although the cost will increase, the charging speed will be increased. If it is considered more economical, M=(2, 3 or 4)*N can be set. In this way, the voltage and current adjustment unit can be switched to charge the cell string by switching the charging channel, which is both economical and can reduce the problem of high battery heating during charging. The processor obtains (battery characteristic data to be charged) SOC (state of charge) curve, current voltage of the cell string, charging voltage and current limit data of the cell string, cell string type, address of the cell string to be charged, and full voltage, inputs it into the charging control strategy model for calculation, and outputs the voltage and current adjustment unit address of the cell string to be charged, the cell string address, and current charging voltage and current data to the register. The register selects the corresponding voltage and current adjustment unit and the cell string to be charged based on the voltage and current adjustment unit address and cell string address to establish a charging link, and controls the voltage and current adjustment unit to output the corresponding voltage and current based on the current charging voltage and current data. The setting of the voltage and current adjustment array in the present invention overcomes the problem that when charging battery vehicles, the DC power output by the AC-DC module is used for direct charging after diversion. This does not distinguish the charging characteristics and loss of each cell string, which can easily cause accelerated cell string loss and spontaneous combustion.

[0039] The voltage and current adjustment unit address, cell string address, and current charging voltage and current data format of the battery to be charged are as follows: {00001111 00011111 00111011 01111101}, where the first 8 bits are used to represent the voltage and current unit address, the second 8 bits are used to represent the cell string address, the third 8 bits are used to represent the voltage, and the fourth 8 bits are used to represent the current. It should be noted that when the battery is charging, a constant current followed by a constant voltage charging method may be used depending on the charging stage. For example, during constant current charging, the voltage bit is represented by all 0s, and the current bit is set to the corresponding current value, i.e., the third and fourth 8 bits are represented by {000000000 00010101}. In the constant voltage charging stage, the current bit is represented by all 0s, and the voltage bit is set to the corresponding voltage value, which can be represented by {00010101 00000000}. The cell type indicates whether it is a sodium ion cell or a lithium ion cell.

[0040] The memory is used to store charging control data and historical charging data;

[0041] The charging control data includes charging control strategy data;

[0042] The historical charging data includes a charging voltage and current curve of each battery cell string during each charging.

[0043] The register controls the voltage and current adjustment array to output corresponding voltage and current to the corresponding battery cell string under the control of the processor;

[0044] The temperature sensor includes a first temperature sensor and a second temperature sensor; the first temperature sensor is used to detect the ambient temperature outside the battery pack, and the second temperature sensor is used to detect the internal temperature of the battery pack;

[0045] The timer is used to record the time when the mains input terminal is connected to the power supply;

[0046] The power signal detection module is used to detect whether the mains input terminal is connected to power.

[0047] Example 2: Based on the sodium-lithium battery vehicle in Example 1, the present invention provides a sodium-lithium battery vehicle charging control method for reducing the problems of spontaneous combustion during charging, battery loss, and facilitating users to use the battery vehicle at any time.

[0048] The charging control steps are as follows:

[0049] S1: When the power signal detection module detects that the mains input terminal is connected to the power supply, the control board is awakened, and the processor controls the voltage and current adjustment array through the register to charge the battery string according to the charging strategy and the characteristic data of the battery to be charged; at the same time, the timer is notified to count the power connection time; the battery string is divided into a sodium battery string and a lithium battery string; the charging strategy includes outputting corresponding charging voltage and current for charging according to the charging characteristics of the sodium battery string and the lithium battery string respectively; the characteristic data of the battery to be charged includes the SOC curve, the current voltage of the battery string, the charging voltage and current limit data of the battery string, the battery string type, the address of the battery string to be charged, and the full voltage;

[0050] Currently, sodium and lithium battery cells produced by battery manufacturers have different voltages and charging voltage-current curves, requiring different charging strategies. Furthermore, as batteries are used, their cell capacity decreases and their charging characteristics change, requiring constant adjustment of charging strategies. Currently available electric vehicles do not account for these changes, which can accelerate battery damage or increase the risk of spontaneous combustion during charging.

[0051] Furthermore, the charging strategy includes a charging control strategy model and a charging characteristic map. The charging characteristic map includes the SOC curve of each cell string, the current voltage of the cell string, the charging voltage and current limit data of the cell string, the cell string type, the address of the cell string to be charged, and the full voltage. During charging, the processor obtains the characteristic data of the battery to be charged from the charging characteristic map in the memory, inputs it into the charging control strategy model for calculation, and writes the voltage and current adjustment unit address, cell string address, and current charging voltage and current data of the cell string to be charged into the register to control the voltage and current adjustment array to select the corresponding voltage and current adjustment unit and the cell string to be charged, and then charges according to the set voltage and current.

[0052] S2: The temperature sensor detects the external ambient temperature and internal temperature of the battery pack. The processor adjusts the charging current of the entire battery pack according to the difference between the external ambient temperature and internal temperature of the battery pack and the upper temperature threshold. The rules are as follows:

[0053] 1. When the ambient temperature outside the battery pack exceeds threshold T1, determine whether the current total charging current of the battery pack is greater than threshold A1. If so, reduce the total charging current to threshold A1; if not, do not adjust the total charging current.

[0054] The threshold T1 is usually set to above 30 degrees. Generally, when the battery pack of an electric vehicle is below 30 degrees, there is a sufficient temperature difference between the temperature of the battery pack during charging and the ambient temperature, which is convenient for heat dissipation and not easy to cause thermal runaway. This is why it is easy to spontaneously combust when charging in summer, but not easy to spontaneously combust when charging in winter.

[0055] Threshold A1 is determined based on the charging current and the heat dissipation equilibrium temperature of the battery pack at a specific ambient temperature. For example, when the external ambient temperature of the battery pack is constant and the battery pack is charging at a certain current, the battery pack will maintain a certain temperature and will not rise further if the heat generated by the charging battery pack is equal to the heat dissipated by the battery pack. This current level can be determined as threshold A1. Therefore, threshold A1 is determined by the manufacturer through extensive experiments based on the battery pack model and the commonly used ambient temperature range selected.

[0056] 2. When the difference between the internal battery pack temperature and the upper temperature threshold is less than a certain value, the current total battery pack charging current is reduced until the battery pack temperature stops rising. The upper temperature threshold is the maximum safe temperature of the battery pack. When the battery pack temperature approaches the maximum safe temperature, the charging current is reduced to prevent the battery pack from heating up, thereby ensuring battery pack safety.

[0057] 3. Stop charging when the internal temperature of the battery pack reaches the upper threshold. In extreme cases, the battery pack temperature may reach the maximum safe temperature. In this case, charging should be stopped immediately to ensure the safety of the battery pack.

[0058] Generally, when the external ambient temperature is high, the same charging current will cause the internal temperature of the battery pack to rise higher. Therefore, when the internal temperature of the battery pack is already high and the external ambient temperature is also high, the charging power needs to be reduced. When the internal temperature of the battery pack reaches the upper threshold, charging should be stopped to allow the battery to cool down automatically and prevent spontaneous combustion.

[0059] S3: The voltage and current detection unit continuously detects the voltage and current at both ends of the charging cell string and stores the detected voltage and current data in the memory. When it is detected that the cell string is fully charged, the processor controls the AC-DC module and the voltage and current adjustment array to stop working, and charging is completed.

[0060] S4: The processor periodically obtains the charging voltage and current data at both ends of the battery string from the memory, uses the capacity loss analysis model to analyze the capacity loss degree of each battery string, corrects the charging capacity, full charge voltage, and battery string charging voltage and current limit data of each battery string, and updates the charging characteristic map.

[0061] When an abnormality is found in a charging cell string, the charging control address of the cell string is blocked in the charging characteristic map so that the cell string is no longer charged during charging. At the same time, an alarm message is generated and sent to the user when the user uses a mobile phone to connect to the Bluetooth module.

[0062] Furthermore, manufacturers regularly send updated capacity loss analysis models and charging strategy algorithms to users' mobile phones. Users connect their mobile phones to the charging system's Bluetooth module to update the capacity loss model to make capacity loss estimation more accurate and achieve more precise charging strategy control.

[0063] Because electric bicycles themselves are a product with a relatively high cost-effectiveness, if the Internet of Things is used, it will increase the burden on users. Therefore, the solution of the present invention does not require the use of the Internet of Things. It can be connected to a mobile phone only through a Bluetooth module, and can upgrade the capacity loss analysis model and charging strategy algorithm.

[0064] Example 3: Based on Example 2, in order to solve the problem that the user may be away from home for a long time due to personal reasons, the battery power will naturally deplete. If the power loss reaches a certain level and is lower than a certain threshold for a period of time, it will cause irreversible damage to the battery. This example performs the following charging control steps:

[0065] SS1: When the battery vehicle is fully charged, the power signal detection module monitors whether the AC input terminal is disconnected from the power supply. When the power supply is disconnected, the timer is cleared and the control board is put into sleep mode to reduce power loss. The process goes to step S1. When the power signal detection module monitors that the power supply is not disconnected, the process goes to step SS2.

[0066] SS2: Determine whether the remaining power of the battery of the electric vehicle is lower than the third threshold; if so, the processor controls the voltage and current adjustment array through the register to charge the battery string according to the charging strategy until the battery power reaches the fourth threshold, the processor controls the AC-DC module and the voltage and current adjustment array to stop working, charging is completed, and go to step SS1; if the remaining power of the battery of the electric vehicle is not lower than the third threshold, go to step SS3.

[0067] Generally, the charge level of a lithium or sodium battery cannot fall below a certain threshold. If it falls below this threshold for a period of time, irreversible damage may occur to the battery. The third threshold value described in the present invention is set to 20% based on experimental data. Furthermore, both lithium and sodium batteries have a certain number of cycles. Excessive charge and discharge cycles can also damage the battery, reducing its service life. However, if the battery is charged to a certain percentage but not fully charged, the damage to the battery is minimal. Therefore, the present invention sets the fourth threshold value to 90% based on experimental data. This way, when a user doesn't use the electric scooter for an extended period, as long as the scooter is connected to the mains, the scooter will, under the control of a controller, repeatedly charge and discharge the battery between 20% and 90%. This prevents damage to the battery due to a lack of charge, nor does it cause loss due to repeated charging and reduced cycle counts. This also provides convenience for users, as they don't need to find someone specifically to charge the battery.

[0068] SS3: Check once every certain time t1 whether the AC power input terminal is disconnected. When the power is disconnected, clear the timer and put the control board into sleep mode to reduce power loss; go to step S1; when the power signal detection module detects that the power is not disconnected, go to step SS2.

[0069] Furthermore, the interval is a certain time t1, and t1 is 10 minutes or 5 minutes.

[0070] In the further step SS2, the third threshold is set to 30%, and the fourth threshold is set to 80%. The third and fourth thresholds can be set by connecting the mobile phone App to the Bluetooth module.

[0071] The above embodiments are intended to illustrate rather than limit the present invention, and those skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. Any changes or substitutions that may be readily conceived by those skilled in the art within the technical scope disclosed herein are intended to be encompassed within the scope of protection of the present invention.

Claims

1. A sodium-lithium battery vehicle charging control method, characterized in that The charging control steps are as follows: S1: When the power signal detection module detects that the mains input terminal is connected to power, the control board is awakened. The control board integrates a processor, a mains input terminal, a Bluetooth module, an AC-DC module, a voltage and current adjustment array, a memory, a voltage and current detection module, a temperature sensor, a register, a timer, and a power signal detection module; The processor controls the voltage and current adjustment array through the register to charge the battery string according to the charging strategy and the characteristic data of the battery to be charged; and at the same time notifies the timer to count the power-on time; S2: The temperature sensor detects the external ambient temperature and the internal temperature of the battery pack, and the processor adjusts the charging current of the entire battery pack according to the external ambient temperature of the battery pack and the difference between the internal temperature of the battery pack and the upper temperature threshold; S3: The voltage and current detection module continuously detects the voltage and current at both ends of the charging cell string and stores the detected voltage and current data in the memory. When it is detected that the cell string is fully charged, the processor controls the AC-DC module and the voltage and current adjustment array to stop working, and charging is completed; S4: The processor periodically obtains charging voltage and current data at both ends of the battery string from the memory, analyzes the capacity loss degree of each battery string using the capacity loss analysis model, corrects the charging capacity, full charge voltage, and battery string charging voltage and current limit data of each battery string, and updates the charging characteristic map; The adjustment rules for adjusting the charging current of the entire battery pack are as follows: (1) When the external ambient temperature of the battery pack exceeds the threshold value T1, determine whether the current total charging current of the battery pack is greater than the threshold value A1. If it is greater than the threshold value A1, reduce the total charging current to the threshold value A1; if it is not greater than the threshold value A1, do not adjust it; (2) When the difference between the internal temperature of the battery pack and the upper temperature threshold is less than a certain value, reduce the total charging current of the current battery pack until the battery pack no longer heats up; (3) When it is detected that the internal temperature of the battery pack reaches the upper threshold, charging is stopped; The charging strategy includes a charging control strategy model and a charging characteristic map; After step S3, the following charging control steps are performed: SS1: When the battery vehicle is fully charged, the power signal detection module monitors whether the mains input terminal is disconnected from the power supply. If the power supply is disconnected, the timer is cleared and the control board is put into sleep mode to reduce power loss. The process then proceeds to step S1. If the power signal detection module monitors that the power supply is not disconnected, the process proceeds to step SS2. SS2: Determine whether the remaining power of the battery of the electric vehicle is lower than the third threshold; If so, the processor controls the voltage and current adjustment array to charge the battery string according to the charging strategy through the register until the battery power reaches the fourth threshold. The processor controls the AC-DC module and the voltage and current adjustment array to stop working, and the charging is completed, and the process goes to step SS1. If the remaining power of the battery car battery is not less than the third threshold, the process goes to step SS3. SS3: Check once every certain time interval t1 whether the AC power input terminal is disconnected. If the power is disconnected, clear the timer and put the control board into sleep mode to reduce power loss; then go to step S1; if the power signal detection module detects that the power is not disconnected, go to step SS2; The third threshold is set to 20%, and the fourth threshold is set to 90%.

2. The charging control method according to claim 1, wherein the charging characteristic map includes the SOC curve of each battery string, the current voltage of the battery string, the charging voltage and current limit data of the battery string, the battery string type, the address of the battery string to be charged, and the full voltage. 3 . The charging control method according to claim 1 , wherein the certain interval t1 is 10 minutes or 5 minutes.

4. A sodium-lithium battery vehicle, characterized in that: The sodium-lithium battery car includes a charging control system and a sodium-lithium hybrid battery cell. The lithium battery cell strings and the sodium battery cell strings are arranged crosswise. Each battery cell string includes multiple battery cells. The battery cell strings are isolated by epoxy resin plates. The charging control system includes a control board; The sodium-lithium battery vehicle can implement the sodium-lithium battery vehicle charging control method described in any one of claims 1-3.

5. The sodium-lithium battery vehicle according to claim 4, wherein the voltage and current adjustment array is used to adjust the output voltage and current to charge each battery string according to the charging control strategy and the characteristic data of the battery to be charged under the control of the processor; the memory is used to store charging control data and historical charging data; the charging control data includes charging control strategy data; the historical charging data includes the charging voltage and current curve of each battery string during each charging.

6. The sodium-lithium battery vehicle according to claim 5, wherein the register controls the voltage and current adjustment array to output the corresponding voltage and current to the corresponding battery cell string under the control of the processor; the temperature sensor includes a first temperature sensor and a second temperature sensor; the first temperature sensor is used to detect the ambient temperature outside the battery pack, and the second temperature sensor is used to detect the internal temperature of the battery pack; the timer is used to record the time when the mains input terminal is connected to the power supply; the power signal detection module is used to detect whether the mains input terminal is connected to the power supply.

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