Low-current charging strategy scheme for truck lithium battery

Abstract

The invention relates to a low-current charging strategy scheme for a truck lithium battery, and the scheme comprises the following steps: S1, judging whether the real-time data information of the lithium battery is satisfied or not according to the real-time data information of the lithium battery, S2, carrying out current limiting to enter a low-current process, and S3, circularly executing the process 1 and the process 2. And a corresponding small-current charging control scheme is automatically adopted, so that the unstable effect of the lithium battery in severe states such as high temperature, high voltage, low voltage, low temperature and large-current faults can be reduced, and the safety of the lithium battery in use is improved. And an important guarantee is provided for maintaining stable operation of the truck lithium battery.

Description

Technical Field

[0001] The present invention relates to the field of truck lithium batteries, and in particular to a low-current charging strategy for truck lithium batteries. Background Art

[0002] With the continuous development of electric vehicle technology, lithium batteries, as the main energy storage device, are increasingly used in the field of electric trucks. However, the charging safety, efficiency and service life of lithium batteries have always been important concerns in the use and development of lithium batteries. Maintaining the safety and stability of lithium batteries during the charging process is particularly critical. If this cannot be guaranteed, it may seriously affect the performance and life of lithium batteries, and even cause safety accidents.

[0003] Traditional lithium battery technologies mainly include fast charging, constant voltage charging and pulse charging. Although these charging technologies have achieved certain results in improving charging speed and convenience, the following technical problems and defects still exist in practical applications:

[0004] 1. Excessively fast high-current charging leads to heat accumulation: Most existing fast charging technologies use high-current charging in the initial stage of charging. Although it can quickly increase the battery power, it will also cause the lithium battery to overheat. If the heat is not dissipated in time, the battery temperature will increase, causing overheating and thermal runaway, thereby damaging the safety and life of the battery.

[0005] 2. Charging current is not flexible enough: The existing technology is not able to respond to the battery status in real time during charging, resulting in the continued use of the same fast charging mode under conditions of high temperature, high voltage or battery aging, thereby increasing battery loss and danger and reducing its performance.

[0006] 3. The impact of the charging process on the battery's electrochemical reaction has not been fully considered: The charging process of lithium batteries is complex, and existing charging strategies often fail to fully consider the electrochemical characteristics of the battery, especially the reaction mechanisms of different batteries at different charging stages, resulting in low charging efficiency and even possible problems such as battery crystallization and electrode aging.

[0007] Therefore, designing a low-current charging strategy for truck lithium batteries to enrich the charging methods and flexibly control the current input under different circumstances is of great significance for improving the safety and stability of charging of truck lithium batteries in different scenarios and ensuring the stable operation of the battery system. Summary of the invention

[0008] The purpose of the present invention is to overcome the shortcomings of the prior art, adapt to the actual needs, and provide a low-current charging strategy for truck lithium batteries to solve the current 1. Excessive high-current rapid charging leads to heat accumulation: Most existing fast charging technologies use high-current charging in the early stage of charging. Although it can quickly increase the battery power, it will also cause the lithium battery to heat up too high. If the heat is not dissipated in time, the temperature of the battery will increase, causing overheating and thermal runaway, thereby damaging the safety and life of the battery. 2. The charging current is not flexible enough: The existing technology is not capable of responding to the battery status in real time during charging, resulting in the continued use of the same fast charging mode under conditions of high temperature, high voltage or battery aging, thereby increasing battery loss and danger and reducing its performance. 3. The impact of the charging process on the electrochemical reaction of the battery is not fully considered: The charging process of lithium batteries is complex, and the existing charging strategies often fail to fully consider the electrochemical characteristics of the battery, especially the reaction mechanism of different batteries at different charging stages, resulting in low charging efficiency, and even technical problems such as battery crystallization and electrode aging.

[0009] In order to achieve the purpose of the present invention, the technical solution adopted by the present invention is: designing a low current charging strategy for truck lithium batteries, including the following steps:

[0010] S1. Determine whether the following conditions are met based on the real-time data of the lithium battery:

[0011] If any of the following conditions are met, the current limiting process will be entered. Otherwise, if all conditions are not met, the current limiting mode will be exited and the current limiting mode will be continuously cycled to determine whether the current limiting mode is met.

[0012] S2, current limiting and entering low current process:

[0013] After the current limit flag is set to 1, the small current MOS is first closed, and then it is determined which of the five current limits mentioned above causes the current limit, and then the corresponding processing flow is entered;

[0014] (1) Current limiting when entering under low pressure or low temperature conditions:

[0015] When the small current MOS is closed, if the charging current is less than 1A for 2 seconds, the small current MOS will be disconnected; when the small current MOS is disconnected, after the continuous timing is full for 2 minutes, the small current MOS will be closed again;

[0016] (2) Current limiting when high voltage, high temperature or high current fault occurs:

[0017] When the small current MOS is closed, if the charging current is less than 5A for 2 seconds, the small current MOS is disconnected;

[0018] S3: This process 1 and 2 are executed in a loop.

[0019] Preferably, the high voltage current limiting comprises the following steps:

[0020] S1. In the charging state, when the high voltage enters the current limit mark position 0, confirm whether the maximum voltage range of the single cell is between 3550mV and 3700mV, and the minimum voltage of the single cell is greater than or equal to 3300mV;

[0021] S2. When the maximum voltage of a single cell is not between 3550mV and 3700mV, and the minimum voltage of a single cell is ≥3300mV, the timer is reset to 0.

[0022] S3, when the maximum voltage of the single cell is between 3550mV and 3700mV, and the minimum voltage of the single cell is greater than or equal to 3300mV, calculate whether the continuous timing meets 5 seconds. If it does not meet 5 seconds, the timing increases. When the continuous timing meets 5 seconds, the high voltage enters the current limiting mark position 1, and the timing is cleared to 0;

[0023] S4, in the charging state, when the high voltage does not enter the current limit mark position 0, the high voltage enters the current limit mark position 1;

[0024] S5. After the high voltage enters the current limiting mark position 1, determine whether the highest voltage of the single cell is greater than or equal to 3700 mV, and the lowest voltage of the single cell is less than or equal to 3350 mV;

[0025] S6. When there is no single-cell maximum voltage >=3700mV and the single-cell minimum voltage <=3350mV, the timer is reset to 0. When the single-cell maximum voltage is >=3700mV and the single-cell minimum voltage is <=3350mV, determine whether the duration is full of 5 seconds;

[0026] S7. When the continuous timing is less than 5 seconds, the timing increases. When the continuous timing is full of 5 seconds, the high voltage enters the current limiting mark position 0 and the timing is cleared to 0.

[0027] Preferably, the low-voltage current limiting comprises the following steps:

[0028] S1. In the charging state, when the low voltage enters the current limit mark position 0, confirm whether the maximum voltage of the single cell is <3300mV, and the minimum voltage of the single cell is ≥2500mV;

[0029] S2. When the highest voltage of a single cell is not less than 3300mV and the lowest voltage of a single cell is not greater than or equal to 2500mV, the timer is reset to 0;

[0030] S3, when the highest voltage of the single cell is less than 3300mV, and the lowest voltage of the single cell is greater than or equal to 2500mV, calculate whether the continuous timing meets 5 seconds. If it does not meet 5 seconds, the timing increases. When the continuous timing meets 5 seconds, the low voltage enters the current limiting mark position 1, and the timing is cleared to 0;

[0031] S4, in the charging state, when the low voltage does not enter the current limit mark position 0, the low voltage enters the current limit mark position 1;

[0032] S5. After the high voltage enters the current limiting mark position 1, determine whether the lowest voltage of the monomer is greater than or equal to 2500mV;

[0033] S6. When there is no single cell minimum voltage ≥ 2500mV, the timer is reset to 0. When the single cell minimum voltage is ≥ 2500mV, it is determined whether the duration is full of 5 seconds.

[0034] S7. When the continuous timing is less than 5 seconds, the timing increases. When the continuous timing is full of 5 seconds, the low pressure enters the current limiting mark position 0 and the timing is cleared.

[0035] Preferably, the high temperature current limiting comprises the following steps:

[0036] S1. In the charging state, when the high temperature enters the current limit mark position 0, confirm whether the maximum temperature of the battery cell is less than or equal to 55°C, and the current is greater than or equal to 50A or the maximum temperature of the battery cell is greater than or equal to 57°C, and it is not fully charged;

[0037] S2. When the maximum temperature of the battery cell is not less than or equal to 55°C, and the current is greater than or equal to 50A, or the maximum temperature of the battery cell is not greater than or equal to 57°C, and the battery is not fully charged, the timer is reset to 0;

[0038] S3, when the maximum temperature of the battery cell is less than or equal to 55°C, and the current is greater than or equal to 50A or the maximum temperature of the battery cell is greater than or equal to 57°C, and it is not fully charged, calculate whether the continuous timing meets 120 seconds. If it does not meet 120 seconds, the timing increases. When the continuous timing meets 120 seconds, the high temperature enters the current limiting flag position 1 and the timing is cleared to 0;

[0039] S4, in the charging state, when the high temperature does not enter the current limit mark position 0, the high temperature enters the current limit mark position 1;

[0040] S5. After the high voltage enters the current limiting mark position 1, determine whether the maximum temperature of the battery cell is less than or equal to 53°C;

[0041] S6. When the maximum temperature of the battery cell is not less than or equal to 53°C, the timer is reset to 0. When the maximum temperature of the battery cell is less than or equal to 53°C, it is determined whether the duration is full of 120 seconds.

[0042] S7. When the continuous timing is less than 120 seconds, the timing increases. When the continuous timing is full of 120 seconds, the high temperature enters the current limiting mark position 0 and the timing is cleared.

[0043] Preferably, the low temperature current limiting comprises the following steps:

[0044] S1. In the charging state, when the low temperature enters the current limit mark position 0, confirm whether the heating MOS is closed, and the maximum temperature of the battery cell is less than or equal to -5°C, and the maximum temperature of the battery cell is greater than -40°C, or the heating MOS is not closed, and the maximum temperature of the battery cell is less than or equal to -5°C, and the maximum temperature of the battery cell is greater than -40°C;

[0045] S2. When the heating MOS is not closed, and the maximum temperature of the battery cell is less than or equal to -5°C, and the maximum temperature of the battery cell is greater than -40°C, or the heating MOS is not closed, and the maximum temperature of the battery cell is less than or equal to -5°C, and the maximum temperature of the battery cell is greater than -40°C, the timer is reset to 0;

[0046] S3. When the heating MOS is closed, and the maximum temperature of the battery cell is less than or equal to -5°C, and the maximum temperature of the battery cell is greater than -40°C, or the heating MOS is not closed, and the maximum temperature of the battery cell is less than or equal to -5°C, and the maximum temperature of the battery cell is greater than -40°C, calculate whether the continuous timing meets 5 seconds. If it does not meet 5 seconds, the timing increases. When the continuous timing meets 5 seconds, the low temperature enters the current limiting mark position 1, and the timing is cleared to 0;

[0047] S4, in the charging state, when the low temperature does not enter the current limit mark position 0, the low temperature enters the current limit mark position 1;

[0048] S5. After the high voltage enters the current limiting mark position 1, determine whether the maximum temperature of the battery cell is greater than or equal to 0°C or the pole temperature is greater than 30°C;

[0049] S6. When there is no cell maximum temperature >=0℃ or pole temperature >30℃, the timer is reset to 0. When the cell maximum temperature >=0℃ or pole temperature >30℃, determine whether the duration is full of 5 seconds.

[0050] S7. When the continuous timing is less than 5 seconds, the timing increases. When the continuous timing is full of 5 seconds, the low temperature enters the current limiting mark position 0 and the timing is cleared.

[0051] Preferably, the high current fault current limiting comprises the following steps:

[0052] S1. In the charging state, when the high current charging fault enters the current limiting flag position and is 0, confirm whether the charging current is above 10A;

[0053] S2. When the charging current is above 10A, check whether there is overcharging, full charging, over-temperature, over-current, charging and short circuit. When there is overcharging, full charging, over-temperature, over-current, charging and short circuit, the high current charging fault enters the current limiting flag position 1 and the timing is cleared to 0;

[0054] S3, in the charging state, when the high current charging fault does not enter the current limiting mark position 0, the high current charging fault enters the current limiting mark position 1;

[0055] S4, after the high current charging fault enters the current limiting flag position 1, determine whether the low current MOS is disconnected;

[0056] S5. When the small current MOS is disconnected, the large current charging fault enters the current limiting flag position 0 and the timing is cleared to 0.

[0057] Compared with the prior art, the present invention has the following beneficial effects:

[0058] The present invention intelligently and accurately controls current input: based on real-time monitored voltage, current, temperature, fault and other data, the low-current charging strategy can automatically determine the current limiting demand and adjust the working state of the low-current MOS to achieve accurate control of the input current of the lithium battery and ensure safety.

[0059] Optimize and enrich charging methods: In terms of charging methods, this strategy adopts the charging effect of small current input. Through intelligent control, flexible processing and combined use of charging current under different severe situations can be achieved to achieve the best safe charging effect.

[0060] Improve safety and stability: Through intelligent management technology and optimized control of charging input current, the safety, reliability and stability of lithium battery use are improved.

[0061] In summary, the truck lithium battery low current charging strategy scheme of the present invention can reduce the unstable effect of lithium batteries under severe conditions such as high temperature, high voltage, low voltage, low temperature and high current fault by real-time monitoring of voltage, current, temperature, fault status, current limiting flag and other data, and automatically adopt corresponding low current charging control schemes, thereby improving the safety of lithium batteries in use. It provides important guarantee for maintaining the stable operation of truck lithium batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 It is a schematic diagram of the low current charging control process of the present invention;

[0063] Figure 2 It is a schematic diagram of the high-voltage current limiting process of the present invention;

[0064] Figure 3 It is a schematic diagram of the low-temperature current limiting process of the present invention;

[0065] Figure 4 It is a schematic diagram of the low-voltage current limiting process of the present invention;

[0066] Figure 5 It is a schematic diagram of the high temperature current limiting process of the present invention;

[0067] Figure 6 It is a schematic diagram of the high current fault current limiting process of the present invention. DETAILED DESCRIPTION

[0068] The present invention is further described below in conjunction with the accompanying drawings and embodiments:

[0069] Example 1: A low current charging strategy for truck lithium batteries, see Figures 1 to 6 , including the following steps:

[0070] S1. Determine whether the following conditions are met based on the real-time data of the lithium battery:

[0071] If any one of the high-voltage current limiting, high-temperature current limiting, low-voltage current limiting, low-temperature current limiting, and high-current fault current limiting is met, the current limiting process is entered; otherwise, if all are not met, the current limiting mode is exited and a continuous cycle is continuously performed to re-judge whether the current limiting mode is met. By real-time monitoring of lithium battery voltage, current, temperature, fault status and other related data, data support is provided for subsequent judgment of whether to enter the current limiting mode and control the low current state. At the same time, current limiting states such as high temperature, high pressure, low voltage, low temperature, and high current fault are obtained: by providing the above-mentioned real-time data related to the lithium battery to determine whether it is necessary to enter the corresponding current limiting mode;

[0072] S2, current limiting and entering low current process:

[0073] After the current limit flag is set to 1, the small current MOS is first closed, and then it is determined which of the five current limits mentioned above causes the current limit, and then the corresponding processing flow is entered;

[0074] (1) Current limiting when entering under low pressure or low temperature conditions:

[0075] When the small current MOS is closed, if the charging current is less than 1A for 2 seconds, the small current MOS will be disconnected; when the small current MOS is disconnected, after the continuous timing is full for 2 minutes, the small current MOS will be closed again;

[0076] (2) Current limiting when high voltage, high temperature or high current fault occurs:

[0077] When the small current MOS is closed, if the charging current is less than 5A for 2 seconds, the small current MOS is disconnected;

[0078] According to the real-time monitored current limiting status flag and low current MOS related flag, the working status of the low current loop can be automatically adjusted to control the current input, so as to achieve accurate control of the current input current of the lithium battery, thereby ensuring the safety of the lithium battery under severe conditions such as high temperature, high voltage, low voltage, low temperature and high current fault;

[0079] S3: This process 1 and 2 are executed in a loop.

[0080] For details, see Figure 2 , the high voltage current limiting comprises the following steps:

[0081] S1. In the charging state, when the high voltage enters the current limit mark position 0, confirm whether the maximum voltage range of the single cell is between 3550mV and 3700mV, and the minimum voltage of the single cell is greater than or equal to 3300mV;

[0082] S2. When the maximum voltage of a single cell is not between 3550mV and 3700mV, and the minimum voltage of a single cell is ≥3300mV, the timer is reset to 0.

[0083] S3, when the maximum voltage of the single cell is between 3550mV and 3700mV, and the minimum voltage of the single cell is greater than or equal to 3300mV, calculate whether the continuous timing meets 5 seconds. If it does not meet 5 seconds, the timing increases. When the continuous timing meets 5 seconds, the high voltage enters the current limiting mark position 1, and the timing is cleared to 0;

[0084] S4, in the charging state, when the high voltage does not enter the current limit mark position 0, the high voltage enters the current limit mark position 1;

[0085] S5. After the high voltage enters the current limiting mark position 1, determine whether the highest voltage of the single cell is greater than or equal to 3700 mV, and the lowest voltage of the single cell is less than or equal to 3350 mV;

[0086] S6. When there is no single-cell maximum voltage >=3700mV and the single-cell minimum voltage <=3350mV, the timer is reset to 0. When the single-cell maximum voltage is >=3700mV and the single-cell minimum voltage is <=3350mV, determine whether the duration is full of 5 seconds;

[0087] S7. When the continuous timing is less than 5 seconds, the timing increases. When the continuous timing is full of 5 seconds, the high voltage enters the current limiting mark position 0 and the timing is cleared to 0.

[0088] For further information, see Figure 3 , the low voltage current limiting comprises the following steps:

[0089] S1. In the charging state, when the low voltage enters the current limit mark position 0, confirm whether the maximum voltage of the single cell is <3300mV, and the minimum voltage of the single cell is ≥2500mV;

[0090] S2. When the highest voltage of a single cell is not less than 3300mV and the lowest voltage of a single cell is not greater than or equal to 2500mV, the timer is reset to 0;

[0091] S3, when the highest voltage of the single cell is less than 3300mV, and the lowest voltage of the single cell is greater than or equal to 2500mV, calculate whether the continuous timing meets 5 seconds. If it does not meet 5 seconds, the timing increases. When the continuous timing meets 5 seconds, the low voltage enters the current limiting mark position 1, and the timing is cleared to 0;

[0092] S4, in the charging state, when the low voltage does not enter the current limit mark position 0, the low voltage enters the current limit mark position 1;

[0093] S5. After the high voltage enters the current limiting mark position 1, determine whether the lowest voltage of the monomer is greater than or equal to 2500mV;

[0094] S6. When there is no single cell minimum voltage ≥ 2500mV, the timer is reset to 0. When the single cell minimum voltage is ≥ 2500mV, it is determined whether the duration is full of 5 seconds.

[0095] S7. When the continuous timing is less than 5 seconds, the timing increases. When the continuous timing is full of 5 seconds, the low pressure enters the current limiting mark position 0 and the timing is cleared.

[0096] It is worth noting that see Figure 4 , the high temperature current limiting comprises the following steps:

[0097] S1. In the charging state, when the high temperature enters the current limit mark position 0, confirm whether the maximum temperature of the battery cell is less than or equal to 55°C, and the current is greater than or equal to 50A or the maximum temperature of the battery cell is greater than or equal to 57°C, and it is not fully charged;

[0098] S2. When the maximum temperature of the battery cell is not less than or equal to 55°C, and the current is greater than or equal to 50A, or the maximum temperature of the battery cell is not greater than or equal to 57°C, and the battery is not fully charged, the timer is reset to 0;

[0099] S3, when the maximum temperature of the battery cell is less than or equal to 55°C, and the current is greater than or equal to 50A or the maximum temperature of the battery cell is greater than or equal to 57°C, and it is not fully charged, calculate whether the continuous timing meets 120 seconds. If it does not meet 120 seconds, the timing increases. When the continuous timing meets 120 seconds, the high temperature enters the current limiting flag position 1 and the timing is cleared to 0;

[0100] S4, in the charging state, when the high temperature does not enter the current limit mark position 0, the high temperature enters the current limit mark position 1;

[0101] S5. After the high voltage enters the current limiting mark position 1, determine whether the maximum temperature of the battery cell is less than or equal to 53°C;

[0102] S6. When the maximum temperature of the battery cell is not less than or equal to 53°C, the timer is reset to 0. When the maximum temperature of the battery cell is less than or equal to 53°C, it is determined whether the duration is full of 120 seconds.

[0103] S7. When the continuous timing is less than 120 seconds, the timing increases. When the continuous timing is full of 120 seconds, the high temperature enters the current limiting mark position 0 and the timing is cleared.

[0104] It is worth noting that see Figure 5 , the low temperature current limiting comprises the following steps:

[0105] S1. In the charging state, when the low temperature enters the current limit mark position 0, confirm whether the heating MOS is closed, and the maximum temperature of the battery cell is less than or equal to -5°C, and the maximum temperature of the battery cell is greater than -40°C, or the heating MOS is not closed, and the maximum temperature of the battery cell is less than or equal to -5°C, and the maximum temperature of the battery cell is greater than -40°C;

[0106] S2. When the heating MOS is not closed, and the maximum temperature of the battery cell is less than or equal to -5°C, and the maximum temperature of the battery cell is greater than -40°C, or the heating MOS is not closed, and the maximum temperature of the battery cell is less than or equal to -5°C, and the maximum temperature of the battery cell is greater than -40°C, the timer is reset to 0;

[0107] S3. When the heating MOS is closed, and the maximum temperature of the battery cell is less than or equal to -5°C, and the maximum temperature of the battery cell is greater than -40°C, or the heating MOS is not closed, and the maximum temperature of the battery cell is less than or equal to -5°C, and the maximum temperature of the battery cell is greater than -40°C, calculate whether the continuous timing meets 5 seconds. If it does not meet 5 seconds, the timing increases. When the continuous timing meets 5 seconds, the low temperature enters the current limiting mark position 1, and the timing is cleared to 0;

[0108] S4, in the charging state, when the low temperature does not enter the current limit mark position 0, the low temperature enters the current limit mark position 1;

[0109] S5. After the high voltage enters the current limiting mark position 1, determine whether the maximum temperature of the battery cell is greater than or equal to 0°C or the pole temperature is greater than 30°C;

[0110] S6. When there is no cell maximum temperature >=0℃ or pole temperature >30℃, the timer is reset to 0. When the cell maximum temperature >=0℃ or pole temperature >30℃, determine whether the duration is full of 5 seconds.

[0111] S7. When the continuous timing is less than 5 seconds, the timing increases. When the continuous timing is full of 5 seconds, the low temperature enters the current limiting mark position 0 and the timing is cleared.

[0112] It is worth mentioning that see Figure 6 , the high current fault current limiting comprises the following steps:

[0113] S1. In the charging state, when the high current charging fault enters the current limiting flag position and is 0, confirm whether the charging current is above 10A;

[0114] S2. When the charging current is above 10A, check whether there is overcharging, full charging, over-temperature, over-current, charging and short circuit. When there is overcharging, full charging, over-temperature, over-current, charging and short circuit, the high current charging fault enters the current limiting flag position 1 and the timing is cleared to 0;

[0115] S3, in the charging state, when the high current charging fault does not enter the current limiting mark position 0, the high current charging fault enters the current limiting mark position 1;

[0116] S4, after the high current charging fault enters the current limiting flag position 1, determine whether the low current MOS is disconnected;

[0117] S5. When the small current MOS is disconnected, the large current charging fault enters the current limiting flag position 0 and the timing is cleared to 0.

[0118] In addition, the components designed in the present invention are all universal standard parts or components known to technical personnel in this field. Their structures and principles can be known to technical personnel through technical manuals or through conventional experimental methods. They can be fully implemented by technical personnel in this field. Needless to say, the content protected by the present invention does not involve improvements to internal structures and methods.

[0119] The embodiments of the present invention disclose preferred embodiments, but are not limited thereto. A person skilled in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and changes. However, as long as they do not deviate from the spirit of the present invention, they are all within the protection scope of the present invention.

Claims

1. A low current charging strategy for truck lithium batteries, characterized in that: The following steps are involved: S1. Determine whether the following conditions are met based on the real-time data of the lithium battery: If any of the following conditions are met, the current limiting process will be entered. Otherwise, if all conditions are not met, the current limiting mode will be exited and the current limiting mode will be continuously cycled to determine whether the current limiting mode is met. S2, current limiting and entering low current process: After the current limit flag is set to 1, the small current MOS is first closed, and then it is determined which of the five current limits mentioned above causes the current limit, and then the corresponding processing flow is entered; (1) Current limiting when entering under low pressure or low temperature conditions: When the small current MOS is closed, if the charging current is less than 1A for 2 seconds, the small current MOS will be disconnected; when the small current MOS is disconnected, after the continuous timing is full for 2 minutes, the small current MOS will be closed again; (2) Current limiting when high voltage, high temperature or high current fault occurs: When the small current MOS is closed, if the charging current is less than 5A for 2 seconds, the small current MOS is disconnected; S3: This process 1 and 2 are executed in a loop.

2. The low current charging strategy for truck lithium batteries as claimed in claim 1, characterized in that: The high voltage current limiting comprises the following steps: S1. In the charging state, when the high voltage enters the current limit mark position 0, confirm whether the maximum voltage range of the single cell is between 3550mV and 3700mV, and the minimum voltage of the single cell is greater than or equal to 3300mV; S2. When the maximum voltage of a single cell is not between 3550mV and 3700mV, and the minimum voltage of a single cell is ≥3300mV, the timer is reset to 0. S3, when the maximum voltage of the single cell is between 3550mV and 3700mV, and the minimum voltage of the single cell is greater than or equal to 3300mV, calculate whether the continuous timing meets 5 seconds. If it does not meet 5 seconds, the timing increases. When the continuous timing meets 5 seconds, the high voltage enters the current limiting mark position 1, and the timing is cleared to 0; S4, in the charging state, when the high voltage does not enter the current limit mark position 0, the high voltage enters the current limit mark position 1; S5. After the high voltage enters the current limiting mark position 1, determine whether the highest voltage of the single cell is greater than or equal to 3700 mV, and the lowest voltage of the single cell is less than or equal to 3350 mV; S6. When there is no single-cell maximum voltage >=3700mV and the single-cell minimum voltage <=3350mV, the timer is reset to 0. When the single-cell maximum voltage is >=3700mV and the single-cell minimum voltage is <=3350mV, determine whether the duration is full of 5 seconds; S7. When the continuous timing is less than 5 seconds, the timing increases. When the continuous timing is full of 5 seconds, the high voltage enters the current limiting mark position 0 and the timing is cleared to 0.

3. The low current charging strategy for truck lithium batteries as claimed in claim 1, characterized in that: The low-voltage current limiting comprises the following steps: S1. In the charging state, when the low voltage enters the current limit mark position 0, confirm whether the maximum voltage of the single cell is <3300mV, and the minimum voltage of the single cell is ≥2500mV; S2. When the highest voltage of a single cell is not less than 3300mV and the lowest voltage of a single cell is not greater than or equal to 2500mV, the timer is reset to 0; S3, when the highest voltage of the single cell is less than 3300mV, and the lowest voltage of the single cell is greater than or equal to 2500mV, calculate whether the continuous timing meets 5 seconds. If it does not meet 5 seconds, the timing increases. When the continuous timing meets 5 seconds, the low voltage enters the current limiting mark position 1, and the timing is cleared to 0; S4, in the charging state, when the low voltage does not enter the current limit mark position 0, the low voltage enters the current limit mark position 1; S5. After the high voltage enters the current limiting mark position 1, determine whether the lowest voltage of the monomer is greater than or equal to 2500mV; S6. When there is no single cell minimum voltage ≥ 2500mV, the timer is reset to 0. When the single cell minimum voltage is ≥ 2500mV, it is determined whether the duration is full of 5 seconds. S7. When the continuous timing is less than 5 seconds, the timing increases. When the continuous timing is full of 5 seconds, the low pressure enters the current limiting mark position 0 and the timing is cleared.

4. The low current charging strategy for truck lithium batteries as claimed in claim 1, characterized in that: The high temperature current limiting comprises the following steps: S1. In the charging state, when the high temperature enters the current limit mark position 0, confirm whether the maximum temperature of the battery cell is less than or equal to 55°C, and the current is greater than or equal to 50A or the maximum temperature of the battery cell is greater than or equal to 57°C, and it is not fully charged; S2. When the maximum temperature of the battery cell is not less than or equal to 55°C, and the current is greater than or equal to 50A, or the maximum temperature of the battery cell is not greater than or equal to 57°C, and the battery is not fully charged, the timer is reset to 0; S3, when the maximum temperature of the battery cell is less than or equal to 55°C, and the current is greater than or equal to 50A or the maximum temperature of the battery cell is greater than or equal to 57°C, and it is not fully charged, calculate whether the continuous timing meets 120 seconds. If it does not meet 120 seconds, the timing increases. When the continuous timing meets 120 seconds, the high temperature enters the current limiting flag position 1 and the timing is cleared to 0; S4, in the charging state, when the high temperature does not enter the current limit mark position 0, the high temperature enters the current limit mark position 1; S5. After the high voltage enters the current limiting mark position 1, determine whether the maximum temperature of the battery cell is less than or equal to 53°C; S6. When the maximum temperature of the battery cell is not less than or equal to 53°C, the timer is reset to 0. When the maximum temperature of the battery cell is less than or equal to 53°C, it is determined whether the duration is full of 120 seconds. S7. When the continuous timing is less than 120 seconds, the timing increases. When the continuous timing is full of 120 seconds, the high temperature enters the current limiting mark position 0 and the timing is cleared.

5. The low current charging strategy for truck lithium batteries as claimed in claim 1, characterized in that: The low temperature current limiting comprises the following steps: S1. In the charging state, when the low temperature enters the current limit mark position 0, confirm whether the heating MOS is closed, and the maximum temperature of the battery cell is less than or equal to -5°C, and the maximum temperature of the battery cell is greater than -40°C, or the heating MOS is not closed, and the maximum temperature of the battery cell is less than or equal to -5°C, and the maximum temperature of the battery cell is greater than -40°C; S2. When the heating MOS is not closed, and the maximum temperature of the battery cell is less than or equal to -5°C, and the maximum temperature of the battery cell is greater than -40°C, or the heating MOS is not closed, and the maximum temperature of the battery cell is less than or equal to -5°C, and the maximum temperature of the battery cell is greater than -40°C, the timer is reset to 0; S3. When the heating MOS is closed, and the maximum temperature of the battery cell is less than or equal to -5°C, and the maximum temperature of the battery cell is greater than -40°C, or the heating MOS is not closed, and the maximum temperature of the battery cell is less than or equal to -5°C, and the maximum temperature of the battery cell is greater than -40°C, calculate whether the continuous timing meets 5 seconds. If it does not meet 5 seconds, the timing increases. When the continuous timing meets 5 seconds, the low temperature enters the current limiting mark position 1, and the timing is cleared to 0; S4, in the charging state, when the low temperature does not enter the current limit mark position 0, the low temperature enters the current limit mark position 1; S5. After the high voltage enters the current limiting mark position 1, determine whether the maximum temperature of the battery cell is greater than or equal to 0°C or the pole temperature is greater than 30°C; S6. When there is no cell maximum temperature >=0℃ or pole temperature >30℃, the timer is reset to 0. When the cell maximum temperature >=0℃ or pole temperature >30℃, determine whether the duration is full of 5 seconds. S7. When the continuous timing is less than 5 seconds, the timing increases. When the continuous timing is full of 5 seconds, the low temperature enters the current limiting mark position 0 and the timing is cleared.

6. The low current charging strategy for truck lithium batteries as claimed in claim 1, characterized in that: The high current fault current limiting comprises the following steps: S1. In the charging state, when the high current charging fault enters the current limiting flag position and is 0, confirm whether the charging current is above 10A; S2. When the charging current is above 10A, check whether there is overcharging, full charging, over-temperature, over-current, charging and short circuit. When there is overcharging, full charging, over-temperature, over-current, charging and short circuit, the high current charging fault enters the current limiting flag position 1 and the timing is cleared to 0; S3, in the charging state, when the high current charging fault does not enter the current limiting mark position 0, the high current charging fault enters the current limiting mark position 1; S4, after the high current charging fault enters the current limiting flag position 1, determine whether the low current MOS is disconnected; S5. When the small current MOS is disconnected, the large current charging fault enters the current limiting flag position 0 and the timing is cleared to 0.

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