Battery charging circuit, battery system and vehicle

Abstract

The utility model discloses a battery charging circuit, a battery system and a vehicle, and the circuit comprises at least two bridge arms which are suitable for being connected to a first battery unit; the first end of each motor winding is connected with the midpoint of one of the at least two bridge arms, so that the motor windings and the at least two bridge arms form a loop, and the second ends of the motor windings are connected together. According to the battery charging circuit, the battery system and the vehicle provided by the utility model, one end of the motor winding is connected to the bridge arm, and the neutral point of the other end is not connected with other devices, so that an N line is canceled, EMC interference is reduced, and by adjusting the conduction mode and the duty ratio of the switching device of the bridge arm, the battery charging circuit can be used for charging the battery without additional hardware. And the battery is heated by heat generated by charging and discharging of the battery.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to a battery charging circuit, a battery system and a vehicle. Background Art

[0002] Under extremely cold conditions, the high-voltage battery pack of new energy vehicles will significantly reduce its power output capacity while driving and its charging capacity when receiving current, resulting in insufficient vehicle power or long charging time. The vehicle needs to be equipped with a high-speed and efficient battery heating system.

[0003] Currently, the motor controller needs to use the N line to realize the functions of motor driving, voltage step-up and voltage step-down, and heating, which will cause certain EMC (Electromagnetic Compatibility) interference. Utility Model Content

[0004] A series of simplified concepts are introduced in the utility model content section, which will be further described in detail in the detailed implementation section. The utility model content section of the utility model does not mean to attempt to define the key features and essential technical features of the technical solution claimed for protection, nor does it mean to attempt to determine the scope of protection of the technical solution claimed for protection.

[0005] The utility model provides a battery charging circuit, comprising:

[0006] at least two bridge arms, the at least two bridge arms being adapted to be connected to a first battery cell;

[0007] The motor windings, each of which has a first end connected to a midpoint of one of the at least two bridge arms, so that the motor winding and the at least two bridge arms form a loop, and the second ends of the motor windings are connected in common.

[0008] Exemplarily, the first bus main line of the at least two bridge arms is electrically connected to the positive electrode of the first battery cell, the second bus main line of the at least two bridge arms is electrically connected to the negative electrode of the first battery cell, and a first relay is arranged between the at least two bridge arms, and the first relay is located on the first bus main line.

[0009] Exemplarily, the at least two bridge arms include a first bridge arm and a second bridge arm, and the relay is arranged between the first bridge arm and the second bridge arm; the first bridge arm is connected to two ends of the first battery unit;

[0010] The battery charging circuit also includes a capacitor connected at two ends of the second bridge arm.

[0011] Exemplarily, each of the at least two bridge arms includes an upper bridge arm switching device and a lower bridge arm switching device connected in series, the upper bridge arm switching device is connected to the first bus main line, the lower bridge arm switching device is connected to the second bus main line, and the midpoint of each bridge arm is located between the upper bridge arm switching device and the lower bridge arm switching device.

[0012] Exemplarily, when the first relay is disconnected and the upper bridge arm switching device of the first bridge arm and the lower bridge arm switching device of the second bridge arm are forward conducted, the first battery cell charges the motor winding; when the first relay is disconnected, the upper bridge arm switching device of the first bridge arm is forward conducted and the upper bridge arm switching device of the second bridge arm is reverse conducted, the first battery cell and the motor winding charge the capacitor.

[0013] Exemplarily, when the first relay is disconnected and the lower bridge arm switching device of the first bridge arm and the upper bridge arm switching device of the second bridge arm are forward conducted, the capacitor charges the motor winding; when the first relay is disconnected, the upper bridge arm switching device of the second bridge arm is forward conducted and the upper bridge arm switching device of the first bridge arm is reverse conducted, the capacitor and the motor winding charge the first battery unit.

[0014] Exemplarily, the battery charging circuit also includes a second battery cell connected in series with the first battery cell, the first battery cell and the second battery cell form a combined battery cell, the two ends of the first bridge arm are respectively connected to the ports of the first battery cell, and the two ends of the second bridge arm are respectively connected to the ports of the combined battery cell.

[0015] Exemplarily, when the first relay is disconnected and the upper bridge arm switching device of the first bridge arm and the lower bridge arm switching device of the second bridge arm are forward conducted, the first battery cell charges the motor winding; when the first relay is disconnected, the upper bridge arm switching device of the first bridge arm is forward conducted and the upper bridge arm switching device of the second bridge arm is reverse conducted, the first battery cell and the motor winding charge the capacitor and the second battery cell.

[0016] Exemplarily, when the first relay is disconnected and the lower bridge arm switching device of the first bridge arm and the upper bridge arm switching device of the second bridge arm are forward conducted, the second battery cell and the capacitor charge the motor winding; when the first relay is disconnected, the upper bridge arm switching device of the second bridge arm is forward conducted and the upper bridge arm switching device of the first bridge arm is reverse conducted, the second battery cell, the capacitor and the motor winding charge the first battery cell.

[0017] Exemplarily, the battery charging circuit further includes: a second relay, wherein the second relay is arranged between the first battery cell and the second battery cell.

[0018] Exemplarily, the capacitor is connected in parallel with the combined battery cell; and further includes an internal capacitor, wherein the internal capacitor includes a capacitor connected in parallel with the first battery cell and / or the second battery cell, respectively.

[0019] The utility model also provides a battery system, comprising any one of the battery charging circuits described above.

[0020] The utility model also provides a vehicle, comprising the battery system as described above.

[0021] According to the battery charging circuit, battery system and vehicle provided by the utility model, one end of the motor winding is connected to the bridge arm, and the neutral point of the other end is not connected to other devices, thereby eliminating the N line and reducing EMC interference. By adjusting the conduction mode and duty cycle of the switching device of the bridge arm, it is possible to heat the battery by utilizing the heat generated by the battery's own charging and discharging without additional hardware. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The following drawings of the present invention are used as a part of the present invention for understanding the present invention. The drawings show the embodiments of the present invention and their descriptions, and are used to explain the principle of the present invention.

[0023] In the attached figure:

[0024] Figure 1 It is a structural schematic diagram of a battery charging circuit according to an embodiment of the utility model;

[0025] Figure 2 is a structural schematic diagram of a battery charging circuit according to another embodiment of the utility model;

[0026] Figure 3 is a turn-on timing diagram of a bridge arm switch device according to an embodiment of the utility model;

[0027] Figure 4 A current schematic diagram of a battery discharge according to an embodiment of the utility model;

[0028] Figure 5 A current schematic diagram of a battery discharge according to an embodiment of the utility model;

[0029] Figure 6 is a current schematic diagram of the discharge of a first battery unit according to another embodiment of the utility model;

[0030] Figure 7is a current schematic diagram of the discharge of a first battery unit according to another embodiment of the utility model;

[0031] Figure 8 is a turn-on timing diagram of a bridge arm switch device according to an embodiment of the utility model;

[0032] Fig. 9 A schematic diagram of current for charging a battery according to an embodiment of the utility model;

[0033] Fig.10 A schematic diagram of current for charging a battery according to an embodiment of the utility model;

[0034] Fig.11 is a current schematic diagram of the discharge of a second battery unit according to another embodiment of the utility model;

[0035] Fig.12 FIG. 4 is a schematic diagram of the current of discharging a second battery unit according to another embodiment of the present invention. DETAILED DESCRIPTION

[0036] In the following description, a large number of specific details are given to provide a more thorough understanding of the utility model. However, it is obvious to those skilled in the art that the utility model can be implemented without one or more of these details. In other examples, in order to avoid confusion with the utility model, some technical features known in the art are not described.

[0037] In order to fully understand the present invention, a detailed description will be provided in the following description to illustrate the battery charging circuit, battery system and vehicle of the present invention. Obviously, the implementation of the present invention is not limited to the specific details familiar to technicians in the field of battery technology. The preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other embodiments.

[0038] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the utility model. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of the features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0039] Now, exemplary embodiments according to the present utility model will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in a variety of different forms and should not be interpreted as being limited to the embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of the present utility model thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art. In the accompanying drawings, for the sake of clarity, the thickness of layers and regions is exaggerated, and the same reference numerals are used to represent the same elements, and thus their description will be omitted.

[0040] In order to avoid EMC interference caused by using N line, the utility model provides a battery charging circuit, including:

[0041] at least two bridge arms, the at least two bridge arms being adapted to be connected to a first battery cell;

[0042] The motor windings, each of which has a first end connected to a midpoint of one of the at least two bridge arms, so that the motor winding and the at least two bridge arms form a loop, and the second ends of the motor windings are connected in common.

[0043] In one embodiment, Figure 1 As shown, the first battery unit also includes a battery internal resistance Rc and an internal capacitor C1, wherein the battery internal resistance Rc includes an internal resistance composed of electrode materials, electrolytes, diaphragm resistances and contact resistances of various parts, and a polarization resistance caused by polarization in an electrochemical reaction. The internal capacitor C1 is connected in parallel at both ends of the first battery unit. The first battery unit first fully charges the capacitor C1 so that the voltage across the capacitor C1 is equal to the power supply voltage of the first battery unit, ensuring that the voltage will not change suddenly in the subsequent stages.

[0044] Furthermore, it also includes a second battery cell connected in series with the first battery cell, the first battery cell and the second battery cell form a combined battery cell, the two ends of the first bridge arm are respectively connected to the ports of the first battery cell, and the two ends of the second bridge arm are respectively connected to the ports of the combined battery cell.

[0045] In one embodiment, Figure 2 As shown, it also includes a second battery unit connected in series with the first battery unit, the first battery unit and the second battery unit form a combined battery unit, preferably, the voltage of the first battery unit and the second battery unit are the same or similar. A second relay K2 is provided between the first battery unit and the second battery unit, specifically, as Figure 2As shown, a second relay K2 is provided between the positive electrode of the first battery cell and the negative electrode of the second battery cell. In addition, a third relay K3 is provided between the negative electrode of the first battery cell and the negative electrode of the second battery cell. The second battery cell may also include a battery internal resistance and an internal capacitor, which will not be described here.

[0046] Exemplarily, each of the at least two bridge arms includes an upper bridge arm switching device and a lower bridge arm switching device connected in series, the upper bridge arm switching device is connected to the first bus main line, the lower bridge arm switching device is connected to the second bus main line, and the midpoint of each bridge arm is located between the upper bridge arm switching device and the lower bridge arm switching device.

[0047] In one embodiment, Figure 1 and Figure 2 As shown, the battery charging circuit includes a three-phase bridge arm, wherein the left bridge arm includes an upper bridge arm switch device Q1 and a lower bridge arm switch device Q4 connected in series, the middle bridge arm includes an upper bridge arm switch device Q2 and a lower bridge arm switch device Q5 connected in series, and the right bridge arm includes an upper bridge arm switch device Q3 and a lower bridge arm switch device Q6 connected in series. Among them, the bridge arm switch devices Q1, Q2, Q3, Q4, Q5, Q6 include but are not limited to MOS (Metal-Oxide-Semiconductor, metal oxide semiconductor) tubes, when the control bridge arm switch devices Q1, Q2, Q3, Q4, Q5, Q6 are closed, forward conduction can be achieved, and when the control bridge arm switch devices Q1, Q2, Q3, Q4, Q5, Q6 are disconnected, reverse conduction can be achieved via the body diode.

[0048] Exemplarily, a first busbar of the at least two bridge arms is electrically connected to the positive electrode of the first battery cell, and a second busbar of the at least two bridge arms is electrically connected to the negative electrode of the first battery cell.

[0049] In one embodiment, Figure 1 In the embodiment shown, the two ends of the three-phase bridge arm are respectively connected to the first bus main line and the second bus main line, wherein the first bus main line is electrically connected to the positive electrode of the first battery unit, and the second bus main line is electrically connected to the negative electrode of the first battery unit. Figure 2 In the embodiment shown, the two ends of the three-phase bridge arm are respectively connected to the first bus main line and the second bus main line, wherein the two ends of the first bus main line are respectively electrically connected to the space between the first battery cell and the second battery cell and the positive electrode of the second battery cell, and the two ends of the second bus main line are respectively electrically connected to the negative electrode of the first battery cell and the positive electrode of the second battery cell.

[0050] Exemplarily, a first relay is arranged between the at least two bridge arms, and the first relay is located on the first busbar. The at least two bridge arms include a first bridge arm and a second bridge arm, and the relay is arranged between the first bridge arm and the second bridge arm; the first bridge arm is connected to both ends of the first battery unit.

[0051] In one embodiment, Figure 1 and Figure 2 As shown, the first relay K1 is arranged on the first bus main line between the first bridge arm (including the left bridge arm and the middle bridge arm) and the second bridge arm (including the right bridge arm), so that the first bridge arm is connected to the first bus main line and directly connected to the positive electrode of the first battery cell or the connection point between the first battery cell and the second battery cell, and the second bridge arm is connected to the first bus main line and connected to the positive electrode of the first battery cell or the connection point between the first battery cell and the second battery cell via the first relay K1.

[0052] Exemplarily, the first end of each motor winding is connected to the midpoint of one of the at least two bridge arms, so that the motor winding and the at least two bridge arms form a loop, and the second end of the motor winding is connected in common. Further, the second end of the motor winding has no N line.

[0053] In one embodiment, Figure 1 and Figure 2 As shown, the motor winding includes three inductors, wherein the first end of the first inductor L1 is connected to the midpoint of the left bridge arm, and the midpoint of the left bridge arm is set between the upper bridge arm switch device Q1 and the lower bridge arm switch device Q4; the first end of the second inductor L2 is connected to the midpoint of the middle bridge arm, and the midpoint of the middle bridge arm is set between the upper bridge arm switch device Q2 and the lower bridge arm switch device Q5; the first end of the third inductor L3 is connected to the midpoint of the right bridge arm, and the midpoint of the right bridge arm is set between the upper bridge arm switch device Q3 and the lower bridge arm switch device Q6.

[0054] In one embodiment, Figure 1 and Figure 2 As shown, the second ends of the three inductors L1, L2, and L3 of the motor winding are connected together to form a neutral point, and there is no N wire at the second end of the motor winding. That is, only one end of the motor winding is connected to the three-phase bridge arm, and the other end has no N wire and is not connected to other devices.

[0055] Exemplarily, the battery charging circuit further includes a capacitor C2, and the capacitor C2 is connected to both ends of the second bridge arm.

[0056] In one embodiment, Figure 1In the example shown, the original internal capacitance of the battery can be split into internal capacitance C1 and capacitance C2, wherein the capacitance of capacitance C2 is smaller than that of internal capacitance C1. The positive electrode of capacitance C2 is connected to the positive electrode of the first battery cell via the first busbar and the first relay K1, and the negative electrode of capacitance C2 is directly connected to the negative electrode of the first battery cell via the second busbar. Figure 2 In the example shown, the capacitor C2 is connected in parallel with the combined battery unit formed by the first battery unit and the second battery unit, and the capacitor C2 is arranged in parallel with the second bridge arm. The positive electrode of the capacitor C2 is directly connected to the positive electrode of the second battery unit, the positive electrode of the capacitor C2 is connected to the connection point between the first battery unit and the second battery unit via the first busbar and the first relay K1, and the negative electrode of the capacitor C2 is directly connected to the negative electrode of the first battery unit.

[0057] By splitting the original internal capacitance of the battery into the internal capacitance C1 and the capacitance C2 in the present application, there is no need to add additional capacitance, the manufacturing process is simple, the cost is low, and the volume is small.

[0058] Exemplarily, when the first relay is disconnected and the upper bridge arm switching device of the first bridge arm and the lower bridge arm switching device of the second bridge arm are forward conducted, the first battery cell charges the motor winding; when the first relay is disconnected and the upper bridge arm switching device of the first bridge arm is forward conducted, the first battery cell and the motor winding charge the capacitor or the first battery cell and the motor winding charge the capacitor and the second battery cell.

[0059] In one embodiment, Figure 1 In the example shown, when driving normally, the first relay K1 is closed, and when the battery is charged, the first relay K1 is opened. Figure 2 In the example shown, during normal driving, the first relay K1 is closed, the second relay K2 is opened, and the third relay K3 is closed. During battery charging, the first relay K1 is opened, the second relay K2 is opened, and the third relay K3 is closed.

[0060] Figure 3 The opening sequence of the bridge arm switch devices Q1, Q2, Q3, Q4, Q5 and Q6 is shown. Among them, the bridge arm switch devices Q1 and Q2 are always in the closed state, that is, they can achieve forward conduction; the bridge arm switch devices Q3, Q4 and Q5 are always in the open state, that is, they cannot achieve forward conduction, but can achieve body diode reverse conduction; the bridge arm switch device Q6 is in the closed / open switching state. Figure 4 and Figure 6 When the upper bridge arm switch device Q1 of the left bridge arm and the upper bridge arm switch device Q2 of the middle bridge arm are forward-conducted, and the lower bridge arm switch device Q6 of the right bridge arm is forward-conducted, the current flows as follows Figure 4 and Figure 6 As shown, at this time, the first battery unit is discharged, and the current flows forward through the upper bridge arm switch device Q1 of the left bridge arm and the upper bridge arm switch device Q2 of the middle bridge arm, and then flows forward through the first inductor L1 and the second inductor L2 of the battery winding, and then flows reversely through the third inductor L3 of the battery winding, and flows forward through the lower bridge arm switch device Q6 of the right bridge arm, so that the first battery unit charges the three inductors L1, L2 and L3 of the motor winding. Next, when the bridge arm switch device Q6 is switched from closed to open, Figure 5 In the example shown, after the current flows in the reverse direction through the third inductor L3 of the battery winding, it flows in the reverse direction through the upper bridge arm switch device Q3 of the right bridge arm via the body diode and flows to the positive electrode of the capacitor C2, so that the first battery cell and the battery winding charge the capacitor C2. Figure 7 In the example shown, after the current flows in the reverse direction through the third inductor L3 of the battery winding, it flows in the reverse direction through the upper bridge arm switching device Q3 of the right bridge arm via the body diode, and flows to the positive electrode of the capacitor C2 and the positive electrode of the second battery cell respectively, thereby enabling the first battery cell and the battery winding to charge the capacitor C2 and the second battery cell.

[0061] Exemplarily, when the first relay is disconnected and the lower bridge arm switching device of the first bridge arm and the upper bridge arm switching device of the second bridge arm are forward conducted, the capacitor charges the motor winding or the second battery cell and the capacitor charge the motor winding; when the first relay is disconnected and the upper bridge arm switching device of the second bridge arm is forward conducted, the capacitor and the motor winding charge the first battery cell or the second battery cell, the capacitor and the motor winding charge the first battery cell.

[0062] Figure 8 The opening timing of the bridge arm switch devices Q1, Q2, Q3, Q4, Q5 and Q6 is shown. Among them, the bridge arm switch devices Q1, Q2, Q6 are always in the open state, that is, they cannot achieve forward conduction, but can achieve body diode reverse conduction; the bridge arm switch device Q3 is always in the closed state,

[0063] That is, forward conduction can be achieved; the bridge arm switch devices Q4 and Q5 are in a closed / open state. When the upper bridge arm switch device Q3 of the right bridge arm is forward-conducted, and the lower bridge arm switch device Q4 of the left bridge arm and the lower bridge arm switch device Q5 of the middle bridge arm are forward-conducted, Fig. 9 In the example shown, capacitor C2 is discharged. Fig.11 In the example shown, both capacitor C2 and the second battery unit are discharged, and the current flows to Fig. 9 and Fig.11As shown, the current flows forward through the upper bridge arm switch device Q3 of the right bridge arm, then flows forward through the third inductor L3 of the battery winding, and then flows reversely through the first inductor L1 and the second inductor L2 of the battery winding, and flows forward through the lower bridge arm switch device Q4 of the left bridge arm and the lower bridge arm switch device Q5 of the middle bridge arm, so that the capacitor C2 or the combination of the capacitor C2 and the second battery unit charges the three inductors L1, L2 and L3 of the motor winding. Next, when the lower bridge arm switch device Q4 of the left bridge arm and the lower bridge arm switch device Q5 of the middle bridge arm are switched from closed to open, the current flows reversely through the first inductor L1 and the second inductor L2 of the battery winding, and then flows reversely through the upper bridge arm switch device Q1 of the left bridge arm and the upper bridge arm switch device Q2 of the middle bridge arm through the body diode, and flows to the positive pole or midpoint of the battery pack. Fig.11 In the example shown, the current flows to the positive electrode of the first battery cell, so that the capacitor C2 and the motor winding charge the first battery cell. Fig.12 In the example shown, current flows to the connection point between the first battery cell and the second battery cell, so that the capacitor C2, the second battery cell and the motor winding charge the first battery cell.

[0064] The utility model also provides a battery system, comprising the battery charging circuit as described above.

[0065] The utility model also provides a vehicle, comprising the battery system as described above.

[0066] According to the battery charging circuit, battery system and vehicle provided by the utility model, one end of the motor winding is connected to the bridge arm, and the neutral point of the other end is not connected to other devices, thereby eliminating the N line and reducing EMC interference. By adjusting the conduction mode and duty cycle of the switching device of the bridge arm, it is possible to heat the battery by utilizing the heat generated by the battery's own charging and discharging without additional hardware.

[0067] The utility model has been described through the above embodiments, but it should be understood that the above embodiments are only for the purpose of example and description, and are not intended to limit the utility model to the scope of the described embodiments. In addition, it can be understood by those skilled in the art that the utility model is not limited to the above embodiments, and more variations and modifications can be made according to the teachings of the utility model, and these variations and modifications all fall within the scope of protection claimed by the utility model. The protection scope of the utility model is defined by the attached claims and their equivalents.

Claims

1. A battery charging circuit, characterized in that: include: at least two bridge arms, the at least two bridge arms being adapted to be connected to a first battery cell; Motor windings, wherein the first end of each of the motor windings is respectively connected to the midpoint of one of the at least two bridge arms, so that the motor winding and the at least two bridge arms form a loop, and the second ends of the motor windings are connected in common; Each of the at least two bridge arms includes an upper bridge arm switching device and a lower bridge arm switching device connected in series, the upper bridge arm switching device is connected to a first bus main line of the two bridge arms, the lower bridge arm switching device is connected to a second bus main line of the two bridge arms, and the midpoint of each bridge arm is located between the upper bridge arm switching device and the lower bridge arm switching device.

2. The battery charging circuit according to claim 1, characterized in that: The first bus main line of the at least two bridge arms is electrically connected to the positive electrode of the first battery unit, the second bus main line of the at least two bridge arms is electrically connected to the negative electrode of the first battery unit, and a first relay is arranged between the at least two bridge arms, and the first relay is located on the first bus main line.

3. The battery charging circuit as claimed in claim 2, characterized in that: The at least two bridge arms include a first bridge arm and a second bridge arm, and the relay is arranged between the first bridge arm and the second bridge arm; the first bridge arm is connected to both ends of the first battery unit; The battery charging circuit also includes a capacitor connected at two ends of the second bridge arm.

4. The battery charging circuit as claimed in claim 3, characterized in that: It also includes a second battery cell connected in series with the first battery cell, the first battery cell and the second battery cell form a combined battery cell, the two ends of the first bridge arm are respectively connected to the ports of the first battery cell, and the two ends of the second bridge arm are respectively connected to the ports of the combined battery cell.

5. The battery charging circuit as claimed in claim 4, characterized in that: Also includes: A second relay is provided between the first battery cell and the second battery cell.

6. The battery charging circuit as claimed in claim 4, characterized in that: The capacitor is connected in parallel with the assembled battery unit; and further comprising: An internal capacitor, wherein the internal capacitor includes a capacitor connected in parallel with the first battery cell and / or the second battery cell respectively.

7. A battery system, characterized in that: A battery charging circuit comprising the battery charging circuit according to any one of claims 1 to 6.

8. A vehicle, characterized in that: A battery system comprising the battery system of claim 7.

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