阅读说明：本技术 电池单元集成电路、动力电池包、电动汽车及方法 (Battery unit integrated circuit, power battery pack, electric vehicle and method ) 是由 刘亚骑 崔晓青 韩为民 王晶 齐大勇 刘明 陈希 杨元健 羿绯 赵新贞 邱志鹏 于 2021-07-22 设计创作，主要内容包括：本公开提出了电池单元集成电路、动力电池包、电动汽车及方法,电池单元集成电路,包括：双向反激变换器、检测单元与数字控制器；双向反激变换器连接至电池单体；检测单元分别检测双向反激变换器的电压数据及电池单体的电压、电流数据并传输至数字控制器；数字控制器根据接收到的电压、电流以及运行模式外部信号确定电池单元集成电路的运行模式,以充电模式、放电模式、故障模式或旁路模式进行工作。(The present disclosure provides a battery cell integrated circuit, a power battery pack, an electric vehicle and a method, wherein the battery cell integrated circuit comprises: the bidirectional flyback converter, the detection unit and the digital controller; the bidirectional flyback converter is connected to the battery monomer; the detection unit respectively detects voltage data of the bidirectional flyback converter and voltage and current data of the single battery and transmits the voltage data and the current data to the digital controller; the digital controller determines an operation mode of the battery cell integrated circuit according to the received voltage, current and an operation mode external signal, and operates in a charge mode, a discharge mode, a fault mode or a bypass mode.)

1. A battery cell integrated circuit, comprising: the bidirectional flyback converter, the detection unit and the digital controller;

the bidirectional flyback converter is connected to a battery monomer;

the detection unit respectively detects voltage data of the bidirectional flyback converter and voltage and current data of the single battery and transmits the voltage data and the current data to the digital controller;

the digital controller determines an operation mode of the battery cell integrated circuit according to the received voltage, current, and an operation mode external signal, and operates in a charge mode, a discharge mode, a fault mode, or a bypass mode.

2. The battery cell integrated circuit of claim 1, wherein the bidirectional flyback converter comprises an input side capacitor, a first relay, a first switching tube, a transformer, a second relay;

the positive pole of the input side capacitor, the first terminal of the first relay, the first terminal of the second relay and the dotted terminal of the primary winding of the transformer are connected together and used as the positive pole of the battery unit integrated circuit;

the negative electrode of the input side capacitor, the second terminal of the first relay, the third terminal of the second relay and the source electrode of the first switching tube are connected together and used as the negative electrode of the battery unit integrated circuit;

the drain electrode of the first switching tube is connected with the different name end of the primary winding of the transformer.

3. The battery cell integrated circuit of claim 1, wherein the bidirectional flyback converter further comprises: a second switch tube and an output side capacitor;

the synonym end of the secondary winding of the transformer is connected with the source electrode of the second switching tube;

the drain electrode of the second switching tube, the second terminal of the second relay, the anode of the output side capacitor and the anode of the battery unit are connected together;

the dotted terminal of the secondary winding of the transformer, the fourth terminal of the second relay, the negative electrode of the output side capacitor and the negative electrode of the battery unit are connected together.

Preferably, the first relay comprises one set of normally open contacts, and the second relay comprises two sets of normally open contacts;

preferably, the first voltage sensor, the second voltage sensor and the current sensor;

the first input end and the second input end of the first voltage sensor are respectively connected with the anode of the battery unit integrated circuit and the cathode of the battery unit integrated circuit;

the first input end and the second input end of the second voltage sensor are respectively connected with the anode of the battery unit and the cathode of the battery unit;

the input end of the current sensor is connected with the battery unit in series.

4. The battery cell integrated circuit of claim 1, wherein the digital controller comprises a battery discharge controller, a battery charge controller, a selection switch, a signal conditioner, and an operation mode identifier.

5. A method of controlling a battery cell integrated circuit, comprising:

the method comprises the following steps of determining an operation mode of a battery unit integrated circuit according to voltage of a battery unit, battery current and an operation mode external signal, wherein 4 operation modes are provided in total, namely a discharge mode, a charge mode, a fault mode and a bypass mode;

preferably, in the charging mode, the signal output by the battery charging controller is used as the input signal of the signal conditioner, 1 group of normally open contacts of the first relay is disconnected, 2 groups of normally open contacts of the second relay are disconnected, the second switch tube is in a turn-off state, and the first switch tube works at high frequency to charge.

6. The method for controlling the battery unit integrated circuit according to claim 5, wherein in the discharging mode, the signal output by the battery discharging controller is used as the input signal of the signal conditioner, 1 group of normally open contacts of the first relay is opened, 2 groups of normally open contacts of the second relay are opened, the second switch tube operates at high frequency, and the first switch tube is in an off state.

7. The method of claim 5, wherein in the fault mode, the first relay has 1 set of normally open contacts closed, the second relay has 2 sets of normally open contacts open, neither the battery discharge controller nor the battery charge controller is active, and both the first switch tube and the second switch tube are in the off state.

8. The method of claim 5, wherein in the bypass mode, the first relay has 1 set of normally open contacts open, the second relay has 2 sets of normally open contacts closed, neither the battery discharge controller nor the battery charge controller is active, and both the first switch tube and the second switch tube are in the off state.

9. A power battery pack, comprising n battery cell ics as claimed in any one of claims 1 to 6, wherein the positive electrode of the ith battery cell ic is connected to the negative electrode of the (i + 1) th battery cell ic, the negative electrode of the 1 st battery cell ic is used as the negative electrode of the electric vehicle integrated power battery pack, the positive electrode of the nth battery cell ic is used as the positive electrode of the electric vehicle integrated power battery pack, and i is 1,2, …, n-1.

10. An electric vehicle, characterized in that the electric vehicle is powered by the power battery pack of claim 9.

Technical Field

The disclosure belongs to the technical field of power electronic converters, and particularly relates to a battery unit integrated circuit, a power battery pack, an electric vehicle and a method.

Background

The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.

In recent years, electric vehicles have been developed more rapidly, but the power battery pack has become an important obstacle to the development of electric vehicles. The power battery pack is generally formed by connecting a plurality of battery units in series and in parallel to obtain a sufficiently high voltage level and a sufficiently large output current, and although the method is simple enough and the cost is the lowest in a plurality of methods, when one battery unit fails, the whole power battery pack cannot work normally. In addition, due to the fact that parameters such as internal parameters and self-discharge rates of each battery unit connected in series are inconsistent, output voltages of the battery units are inconsistent, and stored energy is different, certain battery units are not fully charged in the charging process of the power battery pack, and partial battery units are overcharged, so that the service life of the battery is shortened; during the discharging process of the power battery pack, it may happen that some battery units still have energy, and some battery units are completely discharged, so that the whole power battery pack cannot work when the battery units are not completely discharged.

In order to solve the problem of voltage equalization during charging and discharging of an automobile power battery pack, a passive voltage equalization method and an active voltage equalization method are commonly used at present.

The passive voltage-sharing method is characterized in that each battery unit is connected with an energy-consuming resistor in parallel, and the connection and disconnection of the energy-consuming resistors are determined by detecting the voltage of the battery.

The active voltage-equalizing method usually uses a special power electronic circuit to realize voltage equalization among each unit, such as a switched capacitor method, a switched inductor method, an energy feedback method, and the like, but these methods are based on a series connection structure of battery units, and once any battery unit fails, the whole battery pack still cannot work normally.

The power battery pack of the electric automobile is formed by connecting a plurality of battery units in series, and in the process of repeated charge and discharge, a part of the battery units can generate the phenomenon of overcharge or overdischarge, so that the service life of the power battery pack is greatly restricted; in addition, when any battery unit is in fault, the power battery pack cannot normally operate.

Therefore, the traditional battery pack structure has the phenomenon of voltage unevenness, when any battery unit has a fault, the operation of the fault unit cannot be cut off in time, and the safe and reliable operation of the power battery pack cannot be realized.

Disclosure of Invention

In order to overcome the defects of the prior art, the disclosure provides a battery unit integrated circuit, a battery pack, an electric vehicle and a method, wherein each battery unit is not directly connected in series, so that the phenomenon of uneven voltage in the traditional battery pack structure can be effectively avoided; when any battery unit has a fault, the operation of the fault unit can be cut off, so that the safe and reliable operation of the power battery pack is realized.

In order to achieve the above object, one or more embodiments of the present disclosure provide the following technical solutions:

in a first aspect, a battery cell integrated circuit is disclosed, comprising: the bidirectional flyback converter, the detection unit and the digital controller;

the bidirectional flyback converter is connected to a battery monomer;

the detection unit respectively detects voltage data of the bidirectional flyback converter and voltage and current data of the single battery and transmits the voltage data and the current data to the digital controller;

the digital controller determines an operation mode of the battery cell integrated circuit according to the received voltage, current, and an operation mode external signal, and operates in a charge mode, a discharge mode, a fault mode, or a bypass mode.

According to a further technical scheme, the bidirectional flyback converter comprises an input side capacitor, a first relay, a first switching tube, a transformer and a second relay;

the positive pole of the input side capacitor, the first terminal of the first relay, the first terminal of the second relay and the dotted terminal of the primary winding of the transformer are connected together and used as the positive pole of the battery unit integrated circuit;

the negative electrode of the input side capacitor, the second terminal of the first relay, the third terminal of the second relay and the source electrode of the first switching tube are connected together and used as the negative electrode of the battery unit integrated circuit;

the drain electrode of the first switching tube is connected with the different name end of the primary winding of the transformer.

In a further technical solution, the bidirectional flyback converter further includes: a second switch tube and an output side capacitor;

the synonym end of the secondary winding of the transformer is connected with the source electrode of the second switching tube;

the drain electrode of the second switching tube, the second terminal of the second relay, the anode of the output side capacitor and the anode of the battery unit are connected together;

the dotted terminal of the secondary winding of the transformer, the fourth terminal of the second relay, the negative electrode of the output side capacitor and the negative electrode of the battery unit are connected together.

According to the further technical scheme, the first relay comprises a group of normally open contacts, and the second relay comprises two groups of normally open contacts;

in a further technical solution, the detecting unit includes: a first voltage sensor, a second voltage sensor and a current sensor;

the first input end and the second input end of the first voltage sensor are respectively connected with the anode of the battery unit integrated circuit and the cathode of the battery unit integrated circuit;

the first input end and the second input end of the second voltage sensor are respectively connected with the anode of the battery unit and the cathode of the battery unit;

the input end of the current sensor is connected with the battery unit in series.

In a further technical scheme, the digital controller comprises a battery discharge controller, a battery charge controller, a selection switch, a signal conditioner and an operation mode identifier;

in a second aspect, a method of controlling a battery cell integrated circuit is disclosed, comprising:

the operation mode of the battery unit integrated circuit is determined according to the voltage of the battery unit, the battery current and the external signal of the operation mode, and the total number of the operation modes is 4, namely a discharge mode, a charge mode, a fault mode and a bypass mode.

According to the technical scheme, in the charging mode, a signal output by the battery charging controller serves as an input signal of the signal conditioner, 1 group of normally open contacts of the first relay are disconnected, 2 groups of normally open contacts of the second relay are disconnected, the second switch tube is in a turn-off state, and the first switch tube works at high frequency to charge.

In a further technical scheme, in the discharging mode, a signal output by the battery discharging controller is used as an input signal of the signal conditioner, 1 group of normally open contacts of the first relay are disconnected, 2 groups of normally open contacts of the second relay are disconnected, the second switch tube works at high frequency, and the first switch tube is in a turn-off state.

According to the technical scheme, in the fault mode, 1 group of normally open contacts of the first relay is closed, 2 groups of normally open contacts of the second relay are opened, the battery discharge controller and the battery charge controller do not work, and the first switch tube and the second switch tube are both in a cut-off state.

In the bypass mode, 1 group of normally open contacts of the first relay is disconnected, 2 groups of normally open contacts of the second relay are closed, the battery discharge controller and the battery charge controller do not work, and the first switch tube and the second switch tube are both in a cut-off state.

In a third aspect, a power battery pack is disclosed, which is composed of n battery unit integrated circuits, wherein the positive electrode of the ith battery unit integrated circuit is connected with the negative electrode of the (i + 1) th battery unit integrated circuit, the negative electrode of the 1 st battery unit integrated circuit is used as the negative electrode of the electric automobile integrated power battery pack, the positive electrode of the nth battery unit integrated circuit is used as the positive electrode of the electric automobile integrated power battery pack, and i is 1,2, …, n-1.

In a fourth aspect, an electric automobile is disclosed, and the electric automobile is powered by the power battery pack.

The above one or more technical solutions have the following beneficial effects:

after the power battery pack and the control strategy thereof disclosed by the technical scheme disclosed by the disclosure, the battery units are not directly connected, and the integrated power battery pack can be ensured to normally operate under any condition through 4 operation modes of the bidirectional flyback converter, so that the problem of voltage balancing of the battery units in the traditional series battery pack and the problem of incapability of operating the battery pack due to the fault of any battery unit are avoided.

According to the technical scheme, the bidirectional flyback converter is integrated in front of each battery unit, the bidirectional flyback converter can enable the battery units to operate in a charging mode, a discharging mode, a fault mode and a bypass mode, and the problems of charge-discharge voltage balance of the battery units and normal operation of a battery pack when any battery unit fails are solved.

Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure and are not to limit the disclosure.

Fig. 1 is a structural diagram of an integrated power battery pack structure and a control device of an electric vehicle based on a flyback converter, which is disclosed by the invention;

FIG. 2 is a schematic diagram of an equivalent circuit of a main circuit of a battery unit operating in a charging mode;

FIG. 3 is a schematic diagram of a main circuit equivalent circuit of the battery unit operating in a discharge mode;

FIG. 4 is a schematic diagram of a main circuit equivalent circuit of a battery unit operating in a failure mode;

FIG. 5 is a schematic diagram of an equivalent circuit of a main circuit of the battery unit operating in a bypass mode;

fig. 6 is a schematic diagram of an equivalent circuit of a main circuit when 3 units of an integrated power battery pack consisting of 4 battery units operate in a charging mode and 1 unit operates in a failure mode;

FIG. 7 is a schematic diagram of the connection of 4 cell ICs in a charging mode;

FIG. 8 is a schematic diagram of the connection of 4 cell ICs in discharge mode;

FIG. 9 is a schematic diagram of the connection of 4 cell ICs in bypass mode;

fig. 10-11 are schematic diagrams illustrating that during discharging and charging, the battery unit B3 has a fault, the relay k31 is closed, and the remaining 3 battery units are discharged and charged through the flyback converter;

symbol names in the drawings: u shape_bus-a battery pack bus voltage; c₁₁-a capacitance at the input side of the bidirectional flyback converter; c₁₂-a bidirectional flyback converter output side capacitance; k₁₁1 st relay in bidirectional flyback converterA machine; k₁₂-the 2 nd relay in the bidirectional flyback converter; s₁₁The 1 st switch tube in the bidirectional flyback converter; k₁₂The 2 nd switch tube in the bidirectional flyback converter; t is₁-a transformer in a bidirectional flyback converter; b is₁-a battery unit; u shape_inr-a reference value of the battery cell integrated circuit input voltage; u shape_inf-a battery cell integrated circuit input voltage value; u shape_ine-a cell integrated circuit input voltage error value; i is_fr-a cell discharge current reference value; i is_ff-a cell discharge current value; i is_fe-a cell discharge current error value; u. of_r1-a modulation signal of the battery cell discharge pattern; u shape_Bf-a cell voltage value; u shape_Br-a cell voltage reference value; u shape_Be-a cell voltage error value; i is_cr-a battery cell charging current reference value; i is_cf-a battery cell charging current value; i is_ce-a battery cell charging current error value; u. of_r2-a modulated signal of the battery cell charging mode; u. of_r-a modulation signal of a bidirectional flyback converter; u. of_out-a run mode external signal; u. of_S11-1 st switching tube drive signal; u. of_S12-a 2 nd switching tube drive signal; u. of_K1-selecting a switch drive signal; u. of_K11-a 1 st relay drive signal; u. of_K12-2 nd relay drive signal.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The embodiments and features of the embodiments in the present disclosure may be combined with each other without conflict.

Example one

As shown in fig. 1, the present embodiment discloses a battery unit integrated circuit, which includes a bidirectional flyback converter and a digital controller, wherein the digital controller includes a battery charging controller, a battery discharging controller, a selection switch, a signal conditioner, and an operation mode identifier, and the interconnection relationship and the components thereof will be described in detail below.

The positive electrode of the ith (i-1, 2, …, n-1) battery unit integrated circuit is connected with the negative electrode of the (i-1, 2, …, n-1) battery unit integrated circuit, the negative electrode of the 1 st battery unit integrated circuit is used as the negative electrode of the electric automobile integrated power battery pack, and the positive electrode of the nth battery unit integrated circuit is used as the positive electrode of the electric automobile integrated power battery pack; the ith (i is 1,2, …, n) battery unit integrated circuit comprises a bidirectional flyback converter, a digital controller, a 1 st voltage sensor, a 2 nd voltage sensor and a current sensor; the bidirectional flyback converter comprises an input side capacitor, a 1 st relay, a 1 st switching tube, a transformer, a 2 nd switching tube, a 2 nd relay and an output side capacitor, wherein the 1 st relay comprises a group of normally open contacts, and the 2 nd relay comprises 2 groups of normally open contacts; the positive pole of the input side capacitor, the 1 st terminal of the 1 st relay, the 1 st terminal of the 2 nd relay and the dotted terminal of the primary winding of the transformer are connected together and used as the positive pole of the battery unit integrated circuit; the drain electrode of the 1 st switching tube is connected with the synonym end of the primary winding of the transformer; the negative pole of the input side capacitor, the 2 nd terminal of the 1 st relay, the 3 rd terminal of the 2 nd relay and the source electrode of the 1 st switching tube are connected together and used as the negative pole of the battery unit integrated circuit; the synonym end of the secondary winding of the transformer is connected with the source electrode of the 2 nd switching tube; the drain electrode of the 2 nd switching tube, the 2 nd terminal of the 2 nd relay, the positive electrode of the output side capacitor and the positive electrode of the battery unit are connected together; the dotted terminal of the secondary winding of the transformer, the 4 th terminal of the 2 nd relay, the negative electrode of the output side capacitor and the negative electrode of the battery unit are connected together.

The 1 st input end and the 2 nd input end of the 1 st voltage sensor are respectively connected with the anode of the battery unit integrated circuit and the cathode of the battery unit integrated circuit; the No. 1 input end and the No. 2 input end of the No. 2 voltage sensor are respectively connected with the positive pole of the battery unit and the negative pole of the battery unit; the input end of the current sensor is connected with the battery unit in series.

The digital controller comprises a battery discharge controller, a battery charge controller, a selection switch, a signal conditioner and an operation mode recognizer; in the battery discharge controller, the positive input end of a 1 st subtracter is connected with a reference value of the input voltage of the battery unit integrated circuit, the negative input end of the 1 st subtracter is connected with the output end of a 1 st voltage sensor, the output end of the 1 st subtracter is connected with the input end of an input voltage regulator, and the output end of the input voltage regulator is connected with the positive input end of a 2 nd subtracter; the output end of the current sensor is connected to the output end of the phase inverter, and the output end of the phase inverter is connected to the negative input end of the 2 nd subtracter; the output end of the 2 nd subtracter is connected to the input end of the battery discharge current regulator; in the battery charging controller, the positive input end of a 3 rd subtracter is connected with a reference value of the voltage of a battery unit, the negative input end of the 3 rd subtracter is connected with the output end of a 2 nd voltage sensor, the output end of the 3 rd subtracter is connected with the input end of a battery voltage regulator, and the output end of the battery voltage regulator is connected with the positive input end of a 4 th subtracter; the output end of the current sensor is connected to the negative input end of the 4 th subtracter; the output end of the 4 th subtracter is connected to the input end of the battery charging current regulator; the 2 nd terminal and the 3 rd terminal of the selection switch are respectively connected to the output end of the battery discharge current regulator and the output end of the battery charging current regulator; the 1 st terminal of the selection switch is connected to the 1 st terminal of the signal conditioner; the No. 1 input end, the No. 2 input end and the No. 3 input end of the operation mode identifier are respectively connected with the output end of the No. 2 voltage sensor, the output end of the current sensor and an operation mode external signal; the 1 st output end signal, the 2 nd output end signal and the 3 rd output end signal of the operation mode identifier are respectively used as driving signals of a selector switch, a 1 st relay and a 2 nd relay; the 2 nd terminal of the signal conditioner is connected to an external signal of the running mode; the 3 rd terminal output signal and the 4 th terminal output signal of the signal conditioner are respectively used as the driving signals of the 1 st switch tube and the 2 nd switch tube.

Example II

The embodiment discloses a control method of a battery unit integrated circuit, which comprises the following steps:

the operation mode of the battery unit integrated circuit is determined according to the voltage of the battery unit, the battery current and the external signal of the operation mode, and the total of 4 operation modes are respectively a charging mode, a discharging mode, a fault mode and a bypass mode. The signal of the No. 1 output end of the operation mode recognizer is u_K1The 2 nd output end signal of the operation mode recognizer is u_K11The signal at the 3 rd output end of the operation mode recognizer is u_K12。

When the pattern recognizer determines the charging pattern while the battery pack is being charged, u_K1＝1，u_K11＝0，u_K12When the 1 st terminal of the corresponding selector switch is connected with the 3 rd terminal, a signal output by the battery charging controller is used as an input signal of the signal conditioner, 1 group of normally open contacts of the 1 st relay are disconnected, 2 groups of normally open contacts of the 2 nd relay are disconnected, the 2 nd switching tube is in a turn-off state, the 1 st switching tube works at high frequency, and a corresponding equivalent circuit is shown in fig. 2.

When the battery pack is discharged and the pattern recognizer determines the discharge pattern, u_K1＝-1，u_K11＝0，u_K12When the 1 st terminal of the corresponding selector switch is connected with the 2 nd terminal, the signal output by the battery discharge controller is used as the input signal of the signal conditioner, the 1 st group of normally open contacts of the 1 st relay are disconnected, the 2 nd group of normally open contacts of the 2 nd relay are disconnected, the 2 nd switching tube works at high frequency, the 1 st switching tube is in a turn-off state, and the corresponding equivalent circuit is shown in fig. 3.

When the battery unit is in fault, no matter the battery pack is in charge or discharge mode, the integrated circuit corresponding to the battery unit in fault is identified by the modeThe discriminator determines the fault mode, u_K1＝0，u_K11＝1，u_K12When the terminal 1 of the corresponding selector switch is suspended, the normally open contact 1 of the relay 1 is closed, the normally open contact 2 of the relay 2 is opened, the battery discharge controller and the battery charge controller do not work, the switch tube 1 and the switch tube 2 are both in a cut-off state, and the corresponding equivalent circuit is shown in fig. 4.

When the battery pack is discharged and the cell voltage approaches the input voltage of the integrated circuit, then the cell discharge through the bidirectional flyback converter becomes inefficient, thus increasing the bypass mode. At this time, u_K1＝0，u_K11＝0，u_K12The 1 st terminal of the corresponding selector switch is suspended, the 1 st group of normally open contacts of the 1 st relay is opened, the 2 nd group of normally open contacts of the 2 nd relay is closed, the battery discharge controller and the battery charge controller do not work, the 1 st switch tube and the 2 nd switch tube are both in a cut-off state, and the corresponding equivalent circuit is shown in fig. 5.

It should be noted that the operating principle of the bidirectional flyback converter is the same as that of the ordinary flyback converter, when the battery unit is charged or discharged, only 1 switching tube works at high frequency, and the body diode of the other switching tube is alternately turned on and turned off at high frequency, which is not described herein again.

To better explain the working principle of the battery pack, fig. 6 shows an equivalent circuit of a main circuit of the battery pack, which is composed of 4 battery unit integrated circuits, during charging, wherein if a 3 rd battery unit integrated circuit fails, a 1 st relay normally open contact in the 3 rd battery unit integrated circuit is closed, and the 3 rd battery unit integrated circuit is bypassed entirely and does not participate in working any more; in addition, the 1 st, 2 nd and 4 th battery unit integrated circuits operate in a charging mode, absorb electric energy from the direct current bus and charge the respective battery units through the flyback converter.

EXAMPLE III

The embodiment discloses a power battery pack, which consists of n battery unit integrated circuits, wherein the positive electrode of the ith battery unit integrated circuit is connected with the negative electrode of the (i + 1) th battery unit integrated circuit, the negative electrode of the 1 st battery unit integrated circuit is used as the negative electrode of the integrated power battery pack of the electric automobile, the positive electrode of the nth battery unit integrated circuit is used as the positive electrode of the integrated power battery pack of the electric automobile, and i is 1,2, … and n-1.

Further, the battery pack includes n battery cell integrated circuits, and each battery cell integrated circuit includes a bidirectional flyback converter, a switch, a battery cell, and a digital control device. Each bidirectional flyback converter in each battery unit integrated circuit is connected with each other, the battery units are switched by a digital controller, the battery unit integrated circuits can operate in a charging mode, a discharging mode, a bypass mode and a fault mode, and the operation conditions of the flyback converters are respectively described below by taking 4 battery unit integrated circuits as an example.

Each battery unit of the disclosed embodiment is not directly connected in series, so that the phenomenon of voltage unevenness in the conventional battery pack structure can be effectively avoided; when any battery unit has a fault, the operation of the fault unit can be cut off, so that the safe and reliable operation of the power battery pack is realized.

The digital control device can control the battery units to operate in a charging mode, a discharging mode, a bypass mode and a failure mode, ensures that the battery units operate independently, and avoids the problem of voltage balancing of the battery units in the traditional series battery pack and the problem that the battery pack cannot operate due to the failure of any battery unit.

The battery units are not directly connected, and the integrated power battery pack can be ensured to normally operate under any condition through 4 operation modes of the bidirectional flyback converter, so that the problem of voltage balancing of the battery units in the traditional series battery pack and the problem that the battery pack cannot operate due to faults of any battery unit are solved.

In the charging mode, the connection of the 4-cell integrated circuits is as shown in fig. 7, and at this time, all the contact switches of relays Ki1(i ═ 1,2,3,4) and Ki2(i ═ 1,2,3,4) are in the off state, so Ki1(i ═ 1,2,3,4) and Ki2(i ═ 1,2,3,4) are not shown in fig. 7; energy flows to each battery unit from a direct current bus, namely Ubus in fig. 7 through a flyback converter; the switching tube on the battery side is not controlled at this stage and is used only as a diode; the operation principle of each flyback converter belongs to the prior art, and is not explained herein.

In the discharge mode, the connection of the 4-cell integrated circuits is as shown in fig. 8, and at this time, all the contact switches of relays Ki1(i ═ 1,2,3,4) and Ki2(i ═ 1,2,3,4) are in the off state, so Ki1(i ═ 1,2,3,4) and Ki2(i ═ 1,2,3,4) are not shown in fig. 7; the energy flows from the battery cells to the bus bars.

In the bypass mode, the connection condition of the integrated circuit of the 4 battery units is as shown in fig. 9, in the discharging process of the battery, when the voltage of the 4 battery units is high enough to ensure that the direct current bus can supply power normally, the relay Ki2(i is 1,2,3,4) is switched on, the battery units are directly connected in series through the relay Ki2(i is 1,2,3,4), and the formed bus voltage is the sum of the voltages of the battery units.

Failure mode: when 1 of the battery units has a fault, the unit and the corresponding flyback converter are directly short-circuited, and in the discharging and charging processes of the battery pack corresponding to fig. 10-11, respectively, the battery unit B3 has a fault, the relay k31 is closed, and the rest 3 battery units are discharged and charged through the flyback converter.

Example four

The embodiment discloses an electric automobile, which adopts the power battery pack to supply power.

According to the technical scheme, the battery integration unit is operated in 4 modes of charging, discharging, bypassing and failure under the control of the relay, the potential of the battery unit is utilized to the maximum extent, and the following conditions are ensured: each battery unit is independently charged or discharged, so that the problem of damage to the battery units caused by overcharge or overdischarge of individual battery units in the series battery pack is solved; the bypass mode ensures the high efficiency of the operation of the battery pack; the failure mode ensures that the battery pack can still continue to work when a certain unit fails, and the problem that the battery pack cannot run due to damage of the certain battery unit in the series battery pack is avoided.

Although the present disclosure has been described with reference to specific embodiments, it should be understood that the scope of the present disclosure is not limited thereto, and those skilled in the art will appreciate that various modifications and changes can be made without departing from the spirit and scope of the present disclosure.