Low-voltage battery charging control system and vehicle

Abstract

The application discloses a low-voltage battery power compensation control system and a vehicle, which comprises a low-voltage management controller, an equalization energy storage module and a first switch module, the equalization energy storage module is connected with a power battery through a charge-discharge equalization module, the equalization energy storage module is connected with a low-voltage battery through the first switch module, and the low-voltage management controller is connected with the equalization energy storage module, the first switch module and the low-voltage battery. In the case that the vehicle is parked for a long time and the low-voltage battery is in power shortage, the low-voltage management controller controls the first switch module to be turned on, so that the equalization energy storage module with sufficient power supplies power to the low-voltage battery; the power of the equalization energy storage module is derived from the transferred power of each high state-of-charge single battery cell in the power battery equalization process. The application can utilize the dissipated energy of passive equalization to compensate the power of the low-voltage battery, relieve the power shortage problem of the low-voltage battery and improve the energy efficiency of the power battery system.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of automobile battery management systems, and particularly relates to a low-voltage battery power compensation control system and a vehicle. BACKGROUND

[0002] In a power battery system of a new energy vehicle, due to manufacturing differences, temperature gradient distribution and inconsistent aging of single battery cells, the battery pack needs to rely on the balancing strategy of a battery management system (BMS) to maintain consistency. At present, the mainstream balancing strategy is passive balancing, which dissipates the energy of high state-of-charge (SOC) single battery cells through parallel resistors to release the excess power in the form of heat, so that the SOC of each single battery cell tends to be consistent. However, this method has significant defects: (1) the electric energy generated in the passive balancing process is completely wasted, resulting in a decrease in the overall energy efficiency of the system; (2) the heat generated by resistor dissipation increases the thermal management burden of the battery pack, especially in high-temperature or high-power balancing scenarios, which may cause local temperature rise and accelerate the aging of single battery cells.

[0003] At the same time, the low-voltage battery (12V / 24V / 48V) of a new energy vehicle is prone to power loss when the vehicle is parked for a long time, because the high-voltage system is in hibernation and the static current is continuously consumed. Existing power compensation schemes mostly rely on periodic awakening of the power battery or external charging equipment; however, periodic awakening of the power battery for high-voltage power compensation increases the energy consumption and complexity of the high-voltage system, and external charging equipment relies on user intervention, which is not practical. SUMMARY

[0004] The purpose of the present application is to provide a low-voltage battery power compensation control system and a vehicle, which utilizes the dissipated energy of passive balancing to compensate the low-voltage battery, alleviates the power loss problem of the low-voltage battery, and improves the energy efficiency of the power battery system.

[0005] In a first aspect, the present application provides a low-voltage battery power compensation control system, which comprises a low-voltage management controller, an equalization energy storage module, and a first switching module. The equalization energy storage module is connected to the power battery through a charge-discharge equalization module, and is connected to the low-voltage battery through the first switching module. The low-voltage management controller is connected to the equalization energy storage module, the first switching module, and the low-voltage battery. In the case of long-term parking of the vehicle and power loss of the low-voltage battery, the low-voltage management controller controls the first switching module to be turned on, so that the equalization energy storage module with sufficient power compensates the low-voltage battery. The power of the equalization energy storage module is derived from the transferred power of each high state-of-charge single battery cell in the power balancing process of the power battery.

[0006] Preferably, the rated voltage of the equalization energy storage module is equal to the rated voltage of the low-voltage battery, and it does not need an additional DC / DC converter, so it can directly compensate the low-voltage battery with the equalization energy storage module, simplifying the circuit structure.

[0007] Preferably, the equalization energy storage module adopts an equalization battery cell module, which can ensure the stability of the equalization energy storage module to the low-voltage battery.

[0008] Preferably, if the vehicle is parked for more than a first preset time threshold, it indicates that the vehicle is in a long-term parking state; if the SOC of the low-voltage battery is less than a first preset SOC threshold, it indicates that the low-voltage battery is out of power.

[0009] Preferably, if the SOC of the equalization energy storage module is greater than a second preset SOC threshold, it indicates that the equalization energy storage module has sufficient power; wherein the second preset SOC threshold is greater than the first preset SOC threshold.

[0010] Preferably, during the process of the equalization energy storage module charging the low-voltage battery, when condition one or condition two is met, the low-voltage management controller controls the first switch module to be off, so that the equalization energy storage module stops charging the low-voltage battery, thereby avoiding over-discharge of the equalization energy storage module and over-charge of the low-voltage battery. Condition one, the SOC of the low-voltage battery is greater than or equal to a third preset SOC threshold; Condition two, the SOC of the equalization energy storage module is less than or equal to a fourth preset SOC threshold; wherein the third preset SOC threshold is less than 100%, and the fourth preset SOC threshold is greater than or equal to the first preset SOC threshold and less than the second preset SOC threshold.

[0011] Preferably, the above low-voltage battery charging control system further comprises: a second switch module and a third switch module connected with the low-voltage management controller, a heater for heating the low-voltage battery, and a radiator for cooling the low-voltage battery, the heater is connected with the equalization energy storage module through the second switch module, and the radiator is connected with the equalization energy storage module through the third switch module. During the equalization of the power battery, when the SOC of the equalization energy storage module is greater than or equal to a fifth preset SOC threshold: if the temperature of the low-voltage battery is less than a first preset temperature, the low-voltage management controller controls the second switch module to be on, so that the equalization energy storage module supplies power to the heater, and the heater works to increase the temperature of the low-voltage battery; if the temperature of the low-voltage battery is greater than the first preset temperature, the low-voltage management controller controls the third switch module to be on, so that the equalization energy storage module supplies power to the radiator, and the radiator works to reduce the temperature of the low-voltage battery; thereby, in the case of ensuring the equalization of the power battery and avoiding over-charge of the equalization energy storage module, the low-voltage battery works near the most suitable first preset temperature. Wherein, the fifth preset SOC threshold is greater than the second preset SOC threshold and less than 100%.

[0012] Preferably, in the power battery equalization process, when the SOC of the equalization energy storage module is less than or equal to the sixth preset SOC threshold, the low-voltage management controller controls the second switch module and the third switch module to be turned off, so that the equalization energy storage module stops supplying power to the heater and the radiator, and the heater and the radiator stop working, thereby ensuring that the equalization energy storage module always has sufficient power to supplement the low-voltage battery when the low-voltage battery is out of power. The sixth preset SOC threshold is greater than or equal to the second preset SOC threshold and less than the fifth preset SOC threshold.

[0013] Preferably, the first preset time threshold is 120h, the first preset temperature is 25℃, the first preset SOC threshold is 30%, the second preset SOC threshold is 60%, the third preset SOC threshold is 90%, the fourth preset SOC threshold is 30%, the fifth preset SOC threshold is 95%, and the sixth preset SOC threshold is 70%.

[0014] In a second aspect, the present application provides a vehicle comprising the low-voltage battery power supplement control system.

[0015] The present application is based on the problems of passive equalization dissipation energy and low-voltage battery power supplement demand, and proposes a scheme for supplementing the low-voltage battery with the dissipated energy of passive equalization by directional storage. In the case of ensuring the consistency of the SOC of each single cell, the transferred power of each high state-of-charge single cell in the power battery equalization process is stored in the equalization energy storage module. In the case of long-term parking of the vehicle and out-of-power of the low-voltage battery, the high-voltage starting power battery does not need to be supplemented, and only the power in the equalization energy storage module needs to be transferred to supplement the low-voltage battery. This not only alleviates the problem of low-voltage battery out-of-power, but also improves the energy efficiency of the power battery system. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The figure is the architecture diagram of the low-voltage battery power supplement control system in the embodiment of the present application.

[0017] Figure 2 The figure is the execution flow chart of the low-voltage management controller in the embodiment of the present application. DETAILED DESCRIPTION

[0018] In order to be able to understand the features and technical contents of the embodiments of the present application more thoroughly, the implementation of the embodiments of the present application will be described in detail below with reference to the accompanying drawings, which are only used for reference and do not limit the embodiments of the present application.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used herein are only for the purpose of describing the embodiments of the present application and are not intended to limit the present application.

[0020] In the following description, reference is made to “some embodiments”, which describes a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0021] like Figure 1 As shown, the low-voltage battery charging control system in an embodiment of the present invention includes: a low-voltage management controller 1, a balancing energy storage module 2, and a first switch module 3. The balancing energy storage module 2 is connected to the power battery 5 via the charge and discharge balancing module 4, and the balancing energy storage module 2 is connected to the low-voltage battery 6 via the first switch module 3. The balancing energy storage module 2 has a current sensor. The low-voltage management controller 1 is connected to the balancing energy storage module 2 to obtain the charge and discharge current detected by the current sensor and to perform a real-time estimation of the SOC of the balancing energy storage module based on the charge and discharge current and charge and discharge time. The low-voltage battery 6 has a current sensor and a temperature sensor. The low-voltage management controller 1 is connected to the low-voltage battery 6 to obtain the charge and discharge current detected by the current sensor and the low-voltage battery temperature detected by the temperature sensor and to perform a real-time estimation of the SOC of the low-voltage battery based on the charge and discharge current and charge and discharge time. The low-voltage management controller 1 is connected to the first switch module 3 to control the on / off of the first switch module 3.

[0022] In some embodiments, the rated voltage of the balancing energy storage module 2 is equal to the rated voltage of the low-voltage battery 6. The low-voltage battery 6 can be a low-voltage storage battery or a low-voltage lithium battery.

[0023] In some embodiments, the balanced energy storage module uses a balanced battery cell module.

[0024] In some embodiments, the low-voltage battery recharge control system further includes: a second switch module 7, a third switch module 8, a heater 9 for heating the low-voltage battery, and a radiator 10 for cooling the low-voltage battery. The heater 9 is connected to the balancing energy storage module 2 via the second switch module 7, and the radiator 10 is connected to the balancing energy storage module 2 via the third switch module 8. The low-voltage management controller 1 is connected to the second switch module 7 to control the on / off state of the second switch module 7. The low-voltage management controller 1 is connected to the third switch module 8 to control the on / off state of the third switch module 8.

[0025] like Figure 2 As shown, the low voltage management controller 1 recharges the low voltage battery by executing the following steps:

[0026] S11. Determine whether the vehicle is in a long-term parking state. If yes, execute S12; otherwise, end.

[0027] In some embodiments, if the vehicle is stationary for a time greater than a first preset time threshold, it is determined that the vehicle is in a long-term parking state. As an example, the first preset time threshold is 120 h.

[0028] S12, it is determined whether the low-voltage battery is depleted. If yes, S13 is performed, otherwise, S11 is returned to perform.

[0029] In some embodiments, if the SOC of the low-voltage battery 6 is less than a first preset SOC threshold, it is determined that the low-voltage battery 6 is depleted. As an example, the first preset SOC threshold is 30%.

[0030] S13, it is determined whether the equalization energy storage module has sufficient power. If yes, S14 is performed, otherwise, it is ended.

[0031] In some embodiments, if the SOC of the equalization energy storage module 2 is greater than a second preset SOC threshold, it is determined that the equalization energy storage module has sufficient power. The second preset SOC threshold is greater than the first preset SOC threshold. As an example, the second preset SOC threshold is 60%.

[0032] S14, the first switch module 3 is controlled to be turned on, so that the equalization energy storage module 2 supplies power to the low-voltage battery 6, and then S15 is performed. The power of the equalization energy storage module 2 is derived from the transferred power of each high state of charge cell during the equalization process of the power battery 5.

[0033] In the charging and driving working conditions, the power battery 5 is in a charging / discharging working state, and each front-end analog chip (i.e., the first front-end analog chip, the second front-end analog chip, …, the Nth front-end analog chip) of the BMS monitors the voltage of each cell in real time. Since the states of each cell are different, the control charging and discharging equalization module 4 is opened for equalization at this time, the excess power of the high state of charge cell is transferred to the equalization energy storage module 2, and the SOC consistency of each cell is realized; at the same time, the low-voltage management controller 1 calculates the SOC of the equalization energy storage module 2 and monitors the temperature of the low-voltage battery.

[0034] In the equalization process of the power battery, when the SOC of the equalization energy storage module 2 is greater than or equal to a fifth preset SOC threshold: if the temperature of the low-voltage battery is less than a first preset temperature, the low-voltage management controller 1 controls the second switch module 7 to be turned on, so that the equalization energy storage module 2 supplies power to the heater 9, and the heater 9 works; if the temperature of the low-voltage battery is greater than the first preset temperature, the low-voltage management controller 1 controls the third switch module 8 to be turned on, so that the equalization energy storage module 2 supplies power to the radiator 10, and the radiator 10 works. Generally, the heater 9 and the radiator 10 do not work at the same time. The fifth preset SOC threshold is greater than the second preset SOC threshold and less than 100%. As an example, the fifth preset SOC threshold is 95%.

[0035] In the power battery equalization process, when the SOC of the equalization energy storage module 2 is less than or equal to a sixth preset SOC threshold, the low-voltage management controller 1 controls the second switch module 7 and the third switch module 8 to be turned off, so that the equalization energy storage module 2 stops supplying power to the heater 9 and the radiator 10, and the equalization energy storage module 2 continues to store the equalization power. The sixth preset SOC threshold is greater than or equal to the second preset SOC threshold and less than the fifth preset SOC threshold. As an example, the sixth preset SOC threshold is 70%.

[0036] S15, determine whether condition one or condition two is met, if yes, execute S16, otherwise continue to execute S15.

[0037] The condition one is that the SOC of the low-voltage battery 6 is greater than or equal to a third preset SOC threshold. The condition two is that the SOC of the equalization energy storage module 2 is less than or equal to a fourth preset SOC threshold. The third preset SOC threshold is less than 100%, and the fourth preset SOC threshold is greater than or equal to the first preset SOC threshold and less than the second preset SOC threshold. As an example, the third preset SOC threshold is 90%, and the fourth preset SOC threshold is 30%.

[0038] S16, control the first switch module 3 to be turned off, so that the equalization energy storage module 2 stops charging the low-voltage battery 6, and then the process ends. After the equalization energy storage module charging ends, the low-voltage management controller 1 and the vehicle controller can be powered down and hibernate, and then be woken up at a later time to detect whether the low-voltage battery is depleted.

[0039] In addition, the embodiment of the present application also provides a vehicle, which comprises the above-mentioned low-voltage battery charging control system.

[0040] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A low-voltage battery charging control system, characterized in that: The invention comprises a low-voltage management controller (1), a balancing energy storage module (2) and a first switch module (3); the balancing energy storage module (2) is connected to a power battery (5) via a charge-discharge balancing module (4); the balancing energy storage module (2) is connected to a low-voltage battery (6) via a first switch module (3); and the low-voltage management controller (1) is connected to the balancing energy storage module (2), the first switch module (3) and the low-voltage battery (6); when the vehicle is parked for a long time and the low-voltage battery is low in power, the low-voltage management controller (1) controls the first switch module (3) to conduct, so that the balancing energy storage module (2) with sufficient power can replenish the low-voltage battery (6); The power of the balancing energy storage module (2) is derived from the transferred power of each high-charge state single cell during the balancing process of the power battery (5), and the balancing energy storage module (2) adopts a balancing cell module; if the SOC of the low-voltage battery (6) is less than a first preset SOC threshold, it indicates that the low-voltage battery is low in power; if the SOC of the balancing energy storage module (2) is greater than a second preset SOC threshold, it indicates that the power of the balancing energy storage module is sufficient; During the process of the balancing energy storage module (2) replenishing power to the low-voltage battery (6), when condition one or condition two is met, the low-voltage management controller (1) controls the first switch module (3) to turn off, so that the balancing energy storage module (2) stops replenishing power to the low-voltage battery (6); condition one, the SOC of the low-voltage battery (6) is greater than or equal to a third preset SOC threshold, and the third preset SOC threshold is less than 100%; condition two, the SOC of the balancing energy storage module (2) is less than or equal to a fourth preset SOC threshold, the fourth preset SOC threshold is greater than or equal to the first preset SOC threshold and less than the second preset SOC threshold, and the second preset SOC threshold is greater than the first preset SOC threshold.

2. The low-voltage battery charging control system according to claim 1, characterized in that: The rated voltage of the balancing energy storage module (2) is equal to the rated voltage of the low-voltage battery (6).

3. The low-voltage battery charging control system according to claim 1 or 2, characterized in that: If the vehicle is parked without high pressure for a time period greater than a first preset time threshold, it indicates that the vehicle is in a long-term parking state.

4. The low-voltage battery charging control system according to claim 3, characterized in that: Also includes: A second switch module (7) and a third switch module (8) connected to the low-voltage management controller (1), a heater (9) for heating the low-voltage battery, and a radiator (10) for cooling the low-voltage battery, wherein the heater (9) is connected to the balancing energy storage module (2) via the second switch module (7), and the radiator (10) is connected to the balancing energy storage module (2) via the third switch module (8); during the power battery balancing process, when the SOC of the balancing energy storage module (2) is greater than or equal to a fifth preset SOC threshold value: if the low-voltage battery temperature is less than a first preset temperature, the low-voltage management controller (1) controls the second switch module (7) to be turned on, so that the balancing energy storage module (2) supplies power to the heater (9), and the heater operates; if the low-voltage battery temperature is greater than the first preset temperature, the low-voltage management controller (1) controls the third switch module (8) to be turned on, so that the balancing energy storage module (2) supplies power to the radiator (10), and the radiator operates; wherein the fifth preset SOC threshold value is greater than the second preset SOC threshold value and less than 100%.

5. The low-voltage battery charging control system according to claim 4, characterized in that: During the power battery balancing process, when the SOC of the balancing energy storage module (2) is less than or equal to a sixth preset SOC threshold, the low voltage management controller (1) controls the second switch module (7) and the third switch module (8) to be turned off, so that the balancing energy storage module (2) stops supplying power to the heater (9) and the radiator (10); wherein the sixth preset SOC threshold is greater than or equal to the second preset SOC threshold and less than the fifth preset SOC threshold.

6. The low-voltage battery charging control system according to claim 5, characterized in that: The first preset time threshold is 120h, the first preset temperature is 25°C, the first preset SOC threshold is 30%, the second preset SOC threshold is 60%, the third preset SOC threshold is 90%, the fourth preset SOC threshold is 30%, the fifth preset SOC threshold is 95%, and the sixth preset SOC threshold is 70%.

7. A vehicle, characterized in that: It includes the low-voltage battery charging control system according to any one of claims 1 to 6.

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