Lithium battery system with energy type battery cell and power type battery cell connected in parallel and management method thereof

Abstract

The present invention provides a lithium battery system in which an energy-type battery cell and a power-type battery cell are connected in parallel, and a management method thereof, which belongs to the field of lithium battery energy storage technology. By introducing MOS switch tubes and inductor elements into the lithium battery system in which the energy-type battery cell and the power-type battery cell are connected in parallel, the coordinated and unified auxiliary output of the low-temperature battery and the heating of the lithium battery are achieved, which greatly simplifies the management method of auxiliary control and mutual heating. The management method of the present invention introduces a PWM signal into the MOS switch tube, which can put the lithium battery system in a unidirectional charging mode. In this mode, the power-type battery cell charges and heats the energy-type battery cell, and a battery pack is composed of part of the power-type battery cell charged to the energy-type battery cell and the energy-type battery cell that does not receive charging, and supplies power to an external DC load; in addition, the present invention uses PWM signal control to ensure that the system works efficiently and stably. Compared with traditional auxiliary output and charging and heating methods, the present invention has simpler control and better effects.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium battery energy storage, and in particular relates to a lithium battery system in which energy-type batteries and power-type batteries are connected in parallel, and a management method thereof. Background Art

[0002] With the development of lithium battery technology, the application scenarios of power cells and energy cells are becoming more and more extensive, especially in complex environments and extreme working conditions, which puts higher requirements on the performance of battery systems. Although traditional energy cells have a high energy density and are suitable for long-term power supply needs, they perform poorly in fast discharge and low-temperature environments. Especially in low-temperature environments, the battery capacity decays severely and the performance drops significantly. In contrast, power cells have higher instantaneous power output capabilities and fast charging and discharging characteristics, and are suitable for applications that require high current and high power. However, the energy density of power cells is low, making it difficult to provide stable power for a long time.

[0003] In the prior art, energy cells and power cells are often used separately, and it is impossible to achieve the coordinated work of the two in the same system. This design is particularly problematic in low-temperature environments. Conventional batteries need to rely on external heating devices to increase the temperature at low temperatures to ensure their normal operation, but this increases the complexity and energy consumption of the system. Summary of the invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a lithium battery system with energy type battery cells and power type battery cells connected in parallel and a management method thereof. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0005] In the first aspect, the present invention provides a lithium battery system in which energy type cells and power type cells are connected in parallel, including: multiple power type cells and multiple energy type cells, multiple power type cells are connected in series, and multiple energy type cells are connected in series. A MOS switch tube and a conductive device for controlling the power type cell to charge the energy type cell are arranged between each power type cell and the corresponding energy type cell, and the conductive device is composed of an inductor and a diode in series; the lithium battery system operates in a unidirectional charging mode, and the MOS switch tube controls the power type cell to charge the energy type cell, and a battery group is composed of some power type cells charged to the energy type cell and the energy type cells that are not charged to supply power to an external DC load.

[0006] In a second aspect, the present invention provides a management method for a lithium battery system in which an energy type battery cell and a power type battery cell are connected in parallel, which is used to manage the lithium battery system in which the energy type battery cell and the power type battery cell are connected in parallel in the first aspect, and the management method includes:

[0007] Starting from the first MOS switch tube, a PWM signal with a predetermined duty cycle is passed through the gate of each MOS switch tube in turn, and the remaining MOS switch tubes are turned off, so that the lithium battery system in which the energy type battery cell and the power type battery cell are connected in parallel is in a unidirectional charging mode; in the unidirectional charging mode, a plurality of power type batteries are charged to a plurality of energy type batteries in the following manner: when the PWM signal is at a high level, the power type battery cell charges the energy type battery cell, and a battery pack is formed by part of the power type batteries charged to the energy type batteries and the energy type batteries that are not charged, to supply power to an external DC load.

[0008] Beneficial effects:

[0009] The present invention provides a lithium battery system in which an energy-type battery cell and a power-type battery cell are connected in parallel, and a management method thereof, which belongs to the field of lithium battery energy storage technology. By introducing MOS switch tubes and inductor elements into the lithium battery system in which the energy-type battery cell and the power-type battery cell are connected in parallel, the coordinated and unified auxiliary output of the low-temperature battery and the heating of the lithium battery are achieved, which greatly simplifies the management method of auxiliary control and mutual heating. The management method of the present invention introduces a PWM signal into the MOS switch tube, which can put the lithium battery system in a unidirectional charging mode. In this mode, the power-type battery cell charges and heats the energy-type battery cell, and a battery pack is composed of part of the power-type battery cell charged to the energy-type battery cell and the energy-type battery cell that does not receive charging, and supplies power to an external DC load; in addition, the present invention uses PWM signal control to ensure that the system works efficiently and stably. Compared with traditional auxiliary output and charging and heating methods, the present invention has simpler control and better effects.

[0010] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A schematic diagram of the structure of a lithium battery system in which energy-type batteries and power-type batteries are connected in parallel, provided in an embodiment of the present invention;

[0012] Figure 2 A schematic diagram of a switch mode and a power flow path of a first MOS switch tube in a unidirectional charging mode of a lithium battery system in which an energy-type battery cell and a power-type battery cell are connected in parallel according to an embodiment of the present invention;

[0013] Figure 3 A schematic diagram of the switch mode and power flow path of the second MOS switch tube in a unidirectional charging mode of a lithium battery system in which an energy-type battery cell and a power-type battery cell are connected in parallel according to an embodiment of the present invention;

[0014] Figure 4 A schematic diagram of the switching mode of the third MOS switch tube and the power flow path in the unidirectional charging mode of the lithium battery system in which the energy type battery cell and the power type battery cell are connected in parallel provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0015] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0016] By designing the power type battery cell and the energy type battery cell in parallel, an innovative internal heating function can be realized, thereby improving the working efficiency of the system at low temperatures. In a lithium battery system in which an energy type battery cell and a power type battery cell are connected in parallel, provided by the present invention, a heating function can be provided for the energy type battery cell by utilizing the fast discharge characteristics of the power type battery cell. When the system is in a low temperature environment, the power type battery cell charges and heats up the energy type battery cell through a reasonable control strategy, and utilizes the boost function of the power type battery cell to effectively transfer energy to the energy type battery cell, increase its temperature and restore its working efficiency. This heating process can be achieved without affecting the power supply of the main circuit of the system, while ensuring the efficient and stable operation of the system at low temperatures.

[0017] Therefore, designing a lithium battery system that includes power cells and energy cells in parallel can not only achieve efficient heating functions, but also be able to switch flexibly under different temperature and load conditions to ensure that the system can operate stably in extreme environments. This design with integrated heating function greatly simplifies battery management in low-temperature environments and improves the overall performance and reliability of the battery system.

[0018] Combination Figures 1 to 4 The present invention provides a lithium battery system in which energy-type cells and power-type cells are connected in parallel, including: multiple power-type cells and multiple energy-type cells, multiple power-type cells are connected in series, and multiple energy-type cells are connected in series. A MOS switch tube and a conduction device for controlling the power-type cell to charge the energy-type cell are arranged between each power-type cell and the corresponding energy-type cell, and the conduction device is composed of an inductor and a diode connected in series; the lithium battery system operates in a unidirectional charging mode, and the MOS switch tube controls the power-type cell to charge the energy-type cell, and a battery pack is composed of part of the power-type cells charged to the energy-type cells and the energy-type cells that are not charged to supply power to an external DC load.

[0019] Among them, the energy type battery is a lithium iron phosphate battery, and the power type battery is a nickel-cobalt-manganese ternary lithium battery. The rated voltage of the energy type battery and the power type battery is equal, and the capacity of the power type battery is less than that of the energy type battery.

[0020] It is worth noting that the energy-type battery cell of the present invention is a conventional lithium battery, and the power-type battery cell is a low-temperature lithium battery. The rated voltages of the two are equal or the maximum voltages are equal, but the rated capacities may be unequal, wherein the capacity of the power-type battery cell is much less than that of the energy-type battery cell due to auxiliary output and heating; the power-type battery cell is a nickel-cobalt-manganese ternary lithium battery with a low-viscosity, high-conductivity electrolyte; the energy-type battery cell is a conventional lithium iron phosphate battery; wherein the lithium batteries corresponding to the power-type battery cell and the energy-type battery cell can be replaced by other types of low-temperature lithium batteries and high-energy-density lithium batteries, respectively.

[0021] Continue to refer Figure 1 , the number of power cells and energy cells of the present invention is 6, and the number of MOS switches, inductors and diodes is 3;

[0022] The drain of the first MOS switch tube is connected between an energy type battery cell and a second energy type battery cell, the source is connected to the first end of the first inductor and the positive end of the first diode, the negative end of the first diode is connected between the second energy type battery cell and the third energy type battery cell, and the second end of the first inductor is connected between the second power type battery cell and the third power type battery cell;

[0023] The drain of the second MOS switch tube is connected between the three energy-type battery cells and the fourth energy-type battery cell, the source is connected to the first end of the second inductor and the positive end of the second diode, the negative end of the second diode is connected between the fourth energy-type battery cell and the fifth energy-type battery cell, and the second end of the second inductor is connected between the fourth power-type battery cell and the fifth power-type battery cell;

[0024] The drain of the third MOS switch tube is connected between the five energy type cells and the sixth energy type cell, the source is connected to the first end of the third inductor and the positive end of the third diode, the negative end of the third diode is connected between the sixth energy type cell and the DC load, the second end of the third inductor is connected to the positive end of the sixth power type cell, the positive end of the DC load is connected to the positive end of the sixth energy type cell, and the negative end of the DC load is connected to the negative end of the first energy type cell and the negative end of the first energy type cell.

[0025] Combination Figures 1 to 4 The present invention provides a management method for a lithium battery system in which energy type batteries and power type batteries are connected in parallel, which is used to manage a lithium battery system in which energy type batteries and power type batteries are connected in parallel. The management method includes:

[0026] Starting from the first MOS switch tube, a PWM signal with a predetermined duty cycle is passed through the gate of each MOS switch tube in turn, and the remaining MOS switch tubes are turned off, so that the lithium battery system in which the energy type battery cell and the power type battery cell are connected in parallel is in a unidirectional charging mode; in the unidirectional charging mode, a plurality of power type batteries are charged to a plurality of energy type batteries in the following manner: when the PWM signal is at a high level, the power type battery cell charges the energy type battery cell, and a battery pack is formed by part of the power type batteries charged to the energy type batteries and the energy type batteries that are not charged, to supply power to an external DC load.

[0027] Among them, reservations accounted for 30%.

[0028] refer to Figure 2 , starting from the first MOS switch tube, a PWM signal with a predetermined duty cycle is sequentially input to the gate of each MOS switch tube, and the remaining MOS switch tubes are turned off, so that the lithium battery system in which the energy type battery cell and the power type battery cell are connected in parallel is in a unidirectional charging mode, including:

[0029] A PWM signal with a predetermined duty cycle is supplied to the gate of the first MOS switch tube, and other MOS switch tubes are turned off, so that the lithium battery system in which the energy type battery cell and the power type battery cell are connected in parallel is in a unidirectional charging mode;

[0030] Wherein, in the unidirectional charging mode, when the PWM signal inputted by the first MOS switch tube is at a high level, the first and second power type cells are boosted to charge the first energy type cell, and the second to sixth energy type cells are combined with the first and second power type cells to form a first battery pack to supply power to the DC load;

[0031] When the PWM signal input by the first MOS switch tube is at a low level, the first and second power type batteries charge the first and second energy type batteries, and the third to sixth energy type batteries combine with the first to second power type batteries to form a second battery pack to supply power to the DC load.

[0032] exist Figure 2 In the present invention, the first MOS switch tube is operated, and a PWM signal with a smaller duty cycle is passed to the MOS switch tube SW1, and other MOS switch tubes are turned off; under the high level of PWM, the reference Figure 2 In the upper middle figure, the power cells G1 and G2 will boost the voltage to charge the energy cell C1. The specific power flow path is shown by the closed dotted line on the left. At this time, the energy cells C2~C6 will work with the power cells G1~G2 to supply energy to the DC load. The specific power flow path is shown by the closed dotted line on the right. In the PWM low level state, refer to Figure 2In the lower middle figure, at this time, the power cells G1 and G2 charge the energy cells C1 and C2, and the specific power flow path is shown by the closed dotted line on the left; at this time, the energy cell C2 does not participate in external discharge, and C3~C6 and G1~G2 discharge to the outside. The specific power flow path is shown by the closed dotted line on the right, which can realize charging and heating of the energy cell C2 in a low temperature environment.

[0033] refer to Figure 3 , starting from the first MOS switch tube, a PWM signal with a predetermined duty cycle is sequentially input to the gate of each MOS switch tube, and the remaining MOS switch tubes are turned off, so that the lithium battery system in which the energy type battery cell and the power type battery cell are connected in parallel is in a unidirectional charging mode, including:

[0034] The first MOS switch tube and the third MOS switch tube are turned off, and a PWM signal with a predetermined duty cycle is passed to the gate of the second MOS switch tube, so that the lithium battery system in which the energy type battery cell and the power type battery cell are connected in parallel is in a unidirectional charging mode;

[0035] Among them, in the unidirectional charging mode, when the PWM signal passed into the second MOS switch tube is at a high level, the first to fourth power type cells are boosted to charge the first to third energy type cells, and the fourth to sixth energy type cells are combined with the first to fourth power type cells to form a third battery pack to supply power to the DC load;

[0036] When the PWM signal input by the second MOS switch tube is at a low level, the first to fourth power type batteries charge the first to fourth energy type batteries, and the fifth to sixth energy type batteries combine with the first to fourth power type batteries to form a fourth battery pack to supply power to the DC load.

[0037] The present invention operates the second MOS switch tube, passes a PWM signal with a smaller duty cycle to the MOS switch tube SW2, and turns off the other MOS switch tubes; under the high level of PWM, the reference Figure 3 As shown in the upper middle figure, the power cells G1, G2, G3, and G4 will be boosted to charge the energy cells C1, C2, and C3. The specific power flow path is shown by the closed dotted line on the left. At this time, G1~G4 will work with C4~C6 to supply energy to the DC load. The specific power flow path is shown by the closed dotted line on the right. In the PWM low level state, refer to Figure 3 As shown in the lower middle figure, the power cells G1, G2, G3, and G4 charge the energy cells C1, C2, C3, and C4. The specific power flow path is shown by the closed dotted line on the left. At this time, C5~C6 jointly with G1~G4 discharge to the outside, and C4 does not participate in the external discharge. The specific power flow path is shown by the closed dotted line on the right. Therefore, the energy cell C4 can be charged and heated in a low temperature environment.

[0038] refer to Figure 4 , starting from the first MOS switch tube, a PWM signal with a predetermined duty cycle is sequentially input to the gate of each MOS switch tube, and the remaining MOS switch tubes are turned off, so that the lithium battery system in which the energy type battery cell and the power type battery cell are connected in parallel is in a unidirectional charging mode, including:

[0039] The first MOS switch tube and the second MOS switch tube are turned off, and a PWM signal with a predetermined duty cycle is passed to the gate of the third MOS switch tube, so that the lithium battery system in which the energy type battery cell and the power type battery cell are connected in parallel is in a unidirectional charging mode;

[0040] Among them, in the unidirectional charging mode, when the PWM signal passed through the third MOS switch tube is at a high level, the first to sixth power type cells are boosted to charge the first to fifth energy type cells, and the sixth energy type cell is combined with the first to fifth power type cells to form a fifth battery pack to supply power to the DC load;

[0041] When the PWM signal input by the third MOS switch tube is at a low level, the first to sixth power type batteries charge the first to sixth energy type batteries, and the first to fifth energy type batteries combine with the first to sixth power type batteries to form a sixth battery pack to supply power to the DC load.

[0042] The present invention operates the third MOS switch tube, passes a PWM signal with a smaller duty cycle to the MOS switch tube SW3, and turns off the other MOS switch tubes. Under the high level of PWM, the reference Figure 4 As shown in the upper figure, the power cells G1, G2, G3, G4, G5, and G6 will be boosted to charge the energy cells C1, C2, C3, C4, and C5. The specific power flow path is shown by the closed dotted line on the upper side. At this time, C6 and G1~G5 jointly supply energy to the DC load. The specific power flow path is shown by the closed dotted line on the lower side. In the PWM low level state, refer to Figure 4 As shown in the lower middle figure, the power cells G1, G2, G3, G4, G5, and G6 charge the energy cells C1, C2, C3, C4, C5, and C6, and the specific power flow path is shown by the closed dotted line on the upper side. At this time, G1 to G6 discharge to the outside, and C6 does not participate in the external discharge. The specific power flow path is shown by the closed dotted line on the lower side. The energy cell C6 can be charged and heated in a low temperature environment.

[0043] The present invention needs to use a PWM signal with a smaller duty cycle to control the MOS switch tube, otherwise the inductor voltage will be too high and exceed the limit, resulting in increased energy loss of the power cell, and even overheating and collapse of the lithium battery energy storage system during the heating process.

[0044] In the unidirectional charging mode, the present invention repeatedly starts from the first MOS switch tube, sequentially inputs a PWM signal with a predetermined duty cycle into the gate of each MOS switch tube, and turns off the remaining MOS switch tubes, so that the lithium battery system in which the energy type battery cell and the power type battery cell are connected in parallel is in the unidirectional charging mode, until the temperature of the battery pack composed of the power type battery cell and the energy type battery cell is higher than the set temperature, and then controls the conduction mode of all MOS switch tubes to complete the heating.

[0045] The present invention provides a lithium battery system in which an energy-type battery cell and a power-type battery cell are connected in parallel, and a management method thereof, which belongs to the field of lithium battery energy storage technology. By introducing MOS switch tubes and inductor elements into the lithium battery system in which the energy-type battery cell and the power-type battery cell are connected in parallel, the coordinated and unified auxiliary output of the low-temperature battery and the heating of the lithium battery are achieved, which greatly simplifies the management method of auxiliary control and mutual heating. The management method of the present invention introduces a PWM signal into the MOS switch tube, which can put the lithium battery system in a unidirectional charging mode. In this mode, the power-type battery cell charges and heats the energy-type battery cell, and a battery pack is composed of part of the power-type battery cell charged to the energy-type battery cell and the energy-type battery cell that does not receive charging, and supplies power to an external DC load; in addition, the present invention uses PWM signal control to ensure that the system works efficiently and stably. Compared with traditional auxiliary output and charging and heating methods, the present invention has simpler control and better effects.

[0046] It is worth noting that the terms "first" and "second" in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0047] Although the present application is described herein in conjunction with various embodiments, in the process of implementing the claimed application, those skilled in the art may understand and implement other variations of the disclosed embodiments by reviewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality of components or steps.

[0048] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A lithium battery system in which energy type cells and power type cells are connected in parallel, characterized in that: include: A plurality of power cells and a plurality of energy cells, wherein the plurality of power cells are connected in series, and the plurality of energy cells are connected in series, and a MOS switch tube and a conduction device for controlling the power cells to charge the energy cells are arranged between every two power cells and the corresponding energy cells, and the conduction device is composed of an inductor and a diode in series; the lithium battery system operates in a unidirectional charging mode, the MOS switch tube controls the power cells to charge the energy cells, and a battery pack is formed by some of the power cells charged to the energy cells and the energy cells that are not charged to supply power to an external DC load; The number of the power type battery cells and the number of the energy type battery cells are both 6, and the number of the MOS switch tubes, inductors and diodes are both 3; The drain of the first MOS switch tube is connected between the first energy type battery cell and the second energy type battery cell, the source is connected to the first end of the first inductor and the positive end of the first diode, the negative end of the first diode is connected between the second energy type battery cell and the third energy type battery cell, and the second end of the first inductor is connected between the second power type battery cell and the third power type battery cell; The drain of the second MOS switch tube is connected between the third energy type battery cell and the fourth energy type battery cell, the source is connected to the first end of the second inductor and the positive end of the second diode, the negative end of the second diode is connected between the fourth energy type battery cell and the fifth energy type battery cell, and the second end of the second inductor is connected between the fourth power type battery cell and the fifth power type battery cell; The drain of the third MOS switch tube is connected between the fifth energy type battery cell and the sixth energy type battery cell, the source is connected to the first end of the third inductor and the positive end of the third diode, the negative end of the third diode is connected between the sixth energy type battery cell and the DC load, the second end of the third inductor is connected to the positive end of the sixth power type battery cell, the positive end of the DC load is connected to the positive end of the sixth energy type battery cell, and the negative end of the DC load is connected to the negative end of the first energy type battery cell and the negative end of the first energy type battery cell.

2. The lithium battery system of energy type battery cells and power type battery cells connected in parallel according to claim 1, characterized in that: The energy type battery cell is a lithium iron phosphate battery, and the power type battery cell is a nickel-cobalt-manganese ternary lithium battery.

3. The lithium battery system of energy type battery cells and power type battery cells connected in parallel according to claim 1, characterized in that: The rated voltages of the energy-type battery cell and the power-type battery cell are equal, and the capacity of the power-type battery cell is less than that of the energy-type battery cell.

4. A management method for a lithium battery system in which energy-type batteries and power-type batteries are connected in parallel, characterized in that: A lithium battery system for managing a parallel connection of an energy-type battery cell and a power-type battery cell as claimed in any one of claims 1 to 3, the management method comprising: Starting from the first MOS switch tube, a PWM signal with a predetermined duty cycle is passed through the gate of each MOS switch tube in turn, and the remaining MOS switch tubes are turned off, so that the lithium battery system in which the energy-type battery cell and the power-type battery cell are connected in parallel is in a unidirectional charging mode; in the unidirectional charging mode, the multiple power-type battery cells are charged to the multiple energy-type battery cells in the following manner: when the PWM signal is at a high level, the power-type battery cells charge the energy-type battery cells, and a battery pack is formed by part of the power-type battery cells charged to the energy-type battery cells and the energy-type battery cells that are not charged, to supply power to an external DC load.

5. The management method of a lithium battery system in which energy type batteries and power type batteries are connected in parallel according to claim 4, characterized in that: Starting from the first MOS switch tube, sequentially inputting a PWM signal with a predetermined duty cycle into the gate of each MOS switch tube, and turning off the remaining MOS switch tubes, so that the lithium battery system in which the energy type battery cell and the power type battery cell are connected in parallel is in a unidirectional charging mode, comprises: A PWM signal with a predetermined duty cycle is supplied to the gate of the first MOS switch tube, and other MOS switch tubes are turned off, so that the lithium battery system in which the energy type battery cell and the power type battery cell are connected in parallel is in a unidirectional charging mode; Wherein, in the unidirectional charging mode, when the PWM signal passed through the first MOS switch tube is at a high level, the first and second power-type batteries are boosted to charge the first energy-type battery, and the second to sixth energy-type batteries are combined with the first and second power-type batteries to form a first battery pack to supply power to the DC load; When the PWM signal input by the first MOS switch tube is at a low level, the first and second power type batteries charge the first and second energy type batteries, and the third to sixth energy type batteries are combined with the first to second power type batteries to form a second battery pack to supply power to the DC load.

6. The management method of a lithium battery system in which energy type batteries and power type batteries are connected in parallel according to claim 4, characterized in that: Starting from the first MOS switch tube, sequentially inputting a PWM signal with a predetermined duty cycle into the gate of each MOS switch tube, and turning off the remaining MOS switch tubes, so that the lithium battery system in which the energy type battery cell and the power type battery cell are connected in parallel is in a unidirectional charging mode, comprises: Turning off the first MOS switch tube and the third MOS switch tube, and passing a PWM signal with a predetermined duty cycle to the gate of the second MOS switch tube, so that the lithium battery system in which the energy type battery cell and the power type battery cell are connected in parallel is in a unidirectional charging mode; Wherein, in the unidirectional charging mode, when the PWM signal passed through the second MOS switch tube is at a high level, the first to fourth power type cells are boosted to charge the first to third energy type cells, and the fourth to sixth energy type cells are combined with the first to fourth power type cells to form a third battery pack to supply power to the DC load; When the PWM signal passed through the second MOS switch tube is at a low level, the first to fourth power type batteries charge the first to fourth energy type batteries, and the fifth to sixth energy type batteries combine with the first to fourth power type batteries to form a fourth battery pack to supply power to the DC load.

7. The management method of a lithium battery system in which energy type batteries and power type batteries are connected in parallel according to claim 4, characterized in that: Starting from the first MOS switch tube, sequentially inputting a PWM signal with a predetermined duty cycle into the gate of each MOS switch tube, and turning off the remaining MOS switch tubes, so that the lithium battery system in which the energy type battery cell and the power type battery cell are connected in parallel is in a unidirectional charging mode, comprises: Turning off the first MOS switch tube and the second MOS switch tube, and passing a PWM signal with a predetermined duty cycle to the gate of the third MOS switch tube, so that the lithium battery system in which the energy type battery cell and the power type battery cell are connected in parallel is in a unidirectional charging mode; Wherein, in the unidirectional charging mode, when the PWM signal passed through the third MOS switch tube is at a high level, the first to sixth power type cells are boosted to charge the first to fifth energy type cells, and the sixth energy type cell is combined with the first to fifth power type cells to form a fifth battery pack to supply power to the DC load; When the PWM signal input by the third MOS switch tube is at a low level, the first to sixth power type batteries charge the first to sixth energy type batteries, and the first to fifth energy type batteries combine with the first to sixth power type batteries to form a sixth battery pack to supply power to the DC load.

8. The management method of a lithium battery system in which energy type batteries and power type batteries are connected in parallel according to claim 4, characterized in that: In the unidirectional charging mode, starting from the first MOS switch tube, a PWM signal with a predetermined duty cycle is repeatedly input into the gate of each MOS switch tube in turn, and the remaining MOS switch tubes are turned off, so that the lithium battery system in which the energy-type battery cell and the power-type battery cell are connected in parallel is in a unidirectional charging mode, until the temperature of the battery pack composed of the power-type battery cell and the energy-type battery cell is higher than the set temperature, and then the conduction mode of all MOS switch tubes is controlled to complete the heating.

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