Heating system for power battery and electric vehicle

Abstract

The present disclosure provides a heating system for a power battery and an electric vehicle. The power battery includes a first battery group and a second battery group connected in series. The heating system includes an inverter, an AC motor, a first controller, and a plurality of connecting wires. The midpoints of three bridge arms of the inverter are connected to the tips of three-phase coils of the AC motor in one-to-one correspondence. The ends of the AC motor are connected to each other to form a neutral point. A first end of the connecting wire is connected to the neutral point of the AC motor. A second end of the connecting wire is connected to a connection point between the first battery group and the second battery group. The first controller is configured to input a drive signal to the inverter. The first battery group, the second battery group, the inverter, the AC motor, and the connecting wire form an AC self-heating loop.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This disclosure claims priority to Chinese Patent Application No. 202221001472.5, entitled "HEATING SYSTEM FOR POWER BATTERY AND ELECTRIC VEHICLE," filed on April 28, 2022. The entire contents of the above application are incorporated herein by reference.

[0002] The present disclosure relates to the field of vehicle technology, and more particularly, to a heating system for a power battery and an electric vehicle. [Background technology]

[0003] The characteristics of power batteries are greatly affected by the ambient temperature, and the energy and power characteristics of lithium-ion power batteries are severely attenuated, especially in low-temperature environments. Therefore, it is necessary to heat the battery at low temperatures. In the heating method in which the battery core self-heats using excitation current, how to ensure the safety of the heating process has become an important issue. Summary of the Invention [Means for solving the problem]

[0004] The heating system for a power battery provided in the present disclosure can improve the heating performance of a power battery electric vehicle.

[0005] The objective of the present disclosure is to provide a new technical solution for a heating system for a power battery.

[0006] Another object of the present disclosure is to provide an electric vehicle that includes a heating system.

[0007] According to a first aspect of the present disclosure, a heating system for a power battery is provided. The power battery includes a first battery core group and a second battery core group connected in series. The heating system includes an inverter, an AC motor, a first controller, and a plurality of connecting wires. The inverter includes three bridge arms. A positive electrode of the power battery is connected to an upper bridge arm of the inverter. A negative electrode of the power battery is connected to a lower bridge arm of the inverter. Midpoints of the three bridge arms of the inverter are respectively connected to tips of three-phase coils of an AC motor. Ends of the AC motor are connected to each other to form a neutral point. A first end of the connecting wire is connected to the neutral point of the AC motor. A second end of the connecting wire is connected to a connection point between the first battery core group and the second battery core group. The first controller is configured to input a driving signal to the inverter. The first battery core group, the second battery core group, the inverter, the AC motor, and the connecting wire form an AC current self-heating loop.

[0008] According to an embodiment of the present disclosure, each of the multiple connection lines is provided with a protection circuit, or the multiple connection lines correspond to the same switch.

[0009] The heating system includes a second controller configured to control the switch to turn the connecting line on and off.

[0010] According to an embodiment of the present disclosure, each of the multiple connection lines is provided with a protection circuit, or the multiple connection lines share a protection circuit.

[0011] According to one embodiment of the present disclosure, at least one of the multiple connection lines is connected in series with at least one load.

[0012] According to one embodiment of the present disclosure, the at least one load includes a heating load, the heating load configured to heat the first group of battery cores and / or the second group of battery cores.

[0013] According to an embodiment of the present disclosure, the heating load is attached to a surface of the first battery core group and / or a surface of the second battery core group.

[0014] According to one embodiment of the present disclosure, the heating load is disposed on a first surface of the first battery core group and / or a first surface of the second battery core group, the first surface of the first battery core group being a surface formed by stacking battery core units in the first battery core group, and the first surface of the second battery core group being a surface formed by stacking battery core units in the second battery core group.

[0015] According to one embodiment of the present disclosure, the heating load is positioned on the second surface of the first battery core group and / or the second surface of the second battery core group, where the second surface of the first battery core group is a surface of at least one battery core unit in the first battery core group, and the second surface of the second battery core group is a surface of at least one battery core unit in the second battery core group.

[0016] According to one embodiment of the present disclosure, the heating load corresponds to a low temperature area of ​​the first battery core group and / or the second battery core group, the low temperature area being an area where the temperature of the surface of the battery core group is lower than a first preset value.

[0017] According to a second aspect of the present disclosure, there is provided an electric vehicle including the heating system of the first aspect.

[0018] In the disclosed power battery heating system and electric vehicle, multiple connection lines are added based on the original circuit topology structure of the electric vehicle. The connection lines are connected from the neutral point of the AC motor to the connection point between the first battery core group and the second battery core group. The multiple connection lines share the excitation current and act as redundant backups for each other, significantly improving the safety and stability of the self-heating system.

[0019] Other features and advantages of the present disclosure will become apparent from the following detailed description of illustrative embodiments thereof, which proceeds with reference to the drawings.

[0020] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and are used together to explain the principles of the disclosure. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a block diagram of a heating system for a power battery according to one embodiment of the present disclosure. [Diagram 2] FIG. 2 is a schematic circuit diagram of a heating system for a power battery according to one embodiment of the present disclosure. [Diagram 3] FIG. 2 is a block diagram of a heating system for a power battery according to another embodiment of the present disclosure. [Figure 4] FIG. 2 is a block diagram of a heating system for a power battery according to yet another embodiment of the present disclosure. [Diagram 5] FIG. 2 is a schematic diagram of a structure of a battery core group according to one embodiment of the present disclosure. [Figure 6] FIG. 2 is a schematic diagram of a structure of a battery core group according to one embodiment of the present disclosure. [Figure 7] 1 is a schematic diagram of an electric vehicle according to one embodiment of the present disclosure. [Explanation of symbols]

[0022] 1 First battery core group 2 Second battery core group 3 Inverter 4 AC motor 5,6 Switch 7 First Controller 8 Second Controller P1,P2 connection points; N neutral point S1,S2,S3,S4,S5,S6,S7 connection wire T1, T2, T3, T4, T5, T6 Insulated gate bipolar transistors Q1, Q2, Q3, Q4, Q5, Q6 drive signal VD1, VD2, VD3, VD4, VD5, VD6 diodes DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Various exemplary embodiments herein will be described in detail with reference to the accompanying drawings.

[0024] The following description of at least one exemplary embodiment is intended to be merely illustrative and is not intended to construe any limitation on the embodiments herein or the application or uses of the present specification.

[0025] It should be noted that in the accompanying drawings, like reference numbers or letters refer to like items, and therefore, once an item is defined in one of the accompanying drawings, that item need not be further described in a subsequent accompanying drawing.

[0026] In an electric vehicle, an inverter is connected between a power battery and an AC motor. One of the main functions of the inverter is to convert the DC current output by the power battery into AC current so as to drive the AC motor to rotate and drive the wheel end to rotate. The power battery heating solution in the embodiment of the present disclosure utilizes a circuit topology structure between the power battery, the inverter, and the AC motor.

[0027] In an embodiment of the present disclosure, the power battery includes a first battery core group and a second battery core group connected in series. The heating system includes an inverter, an AC motor, a first controller, and a plurality of connecting wires. The inverter includes three bridge arms. The positive pole of the power battery is connected to an upper bridge arm of the inverter. The negative pole of the power battery is connected to a lower bridge arm of the inverter. The midpoints of the three bridge arms of the inverter are respectively connected to the tips of the three-phase coils of the AC motor. The ends of the AC motor are connected to each other to form a neutral point. A first end of the connecting wire is connected to the neutral point of the AC motor, and a second end of the connecting wire is connected to a connection point between the first battery core group and the second battery core group.

[0028] In an embodiment of the present disclosure, the first battery core group, the second battery core group, the inverter, the AC motor and the connecting wire form an AC current self-heating loop. In an embodiment of the present disclosure, the first controller is configured to input a driving signal to the inverter. Under the influence of the driving signal, the inverter alternately turns on the first battery core group and the AC motor and the second battery core group and the AC motor, so that the first battery core group and the second battery core group alternately charge each other, thereby heating the first battery core group and the second battery core group.

[0029] The heating system for power battery in the embodiment of the present disclosure includes multiple connecting wires. The multiple connecting wires share the excitation current, which reduces the current on a single connecting wire and improves the safety of the heating system. At the same heating efficiency, the design of multiple connecting wires can prevent the current on a single connecting wire from being excessive, which prevents the connecting wire from burning due to excessive current, thereby improving the safety of the heating system.

[0030] Multiple connecting lines are in a parallel relationship and may function as redundant backups for each other. The failure of one connecting line will not affect the normal operation of the other connecting lines, and the power battery can still be heated, which greatly improves the safety and stability of the self-heating system.

[0031] Furthermore, since a single connecting wire needs to carry a small amount of excitation current, the requirements for the material and radius of the connecting wire are reduced, which is beneficial to reducing the cost of the heating system.

[0032] Hereinafter, a heating system for a power battery provided in an embodiment of the present disclosure will be described with reference to Figs. 1 to 4.

[0033] 1 and 2, the power battery includes a first battery core group 1 and a second battery core group 2 connected in series. The heating system includes an inverter 3, an AC motor 4, a first controller 7, a connection line S1, and a connection line S2.

[0034] The AC motor 4 is star-connected, and three ends of the three-phase coils (coil A, coil B, and coil C) are connected together as a common end. The common end is a neutral point N of the AC motor 4.

[0035] The inverter 3 includes three bridge arms. The positive electrode of the power battery is connected to the upper bridge arm of the inverter 3. The negative electrode of the power battery is connected to the lower bridge arm of the inverter 3. The midpoints of the three bridge arms of the inverter 3 are respectively connected to the tips of the three-phase coils of the AC motor 4.

[0036] A first end of the connection line S1 is connected to the neutral point N of the AC motor 4, and a second end of the connection line S1 is connected to a connection point P1 between the first battery core group 1 and the second battery core group 2. A first end of the connection line S2 is connected to the neutral point N of the AC motor, and a second end of the connection line S2 is connected to a connection point P2 between the first battery core group 1 and the second battery core group 2.

[0037] In one example, the first battery core group 1 and the second battery core group 2 belong to the same battery pack. The battery pack provides all positive ports, all negative ports, a third port leading from a connection point P1, and a fourth port leading from a connection point P2 to the outside. The second end of the connection line S1 is connected to the connection point P1 between the first battery core group 1 and the second battery core group 2 through the third port. The second end of the connection line S2 is connected to the connection point P2 between the first battery core group 1 and the second battery core group 2 through the fourth port. In another example, the first battery core group 1 and the second battery core group 2 belong to different battery packs.

[0038] The first controller 7 inputs a drive signal to the inverter 3 to control the inverter 3 to alternately turn on the first battery core group 1 and the AC motor 4 and the second battery core group 2 and the AC motor 4, thereby configuring the first battery core group 1 and the second battery core group 2 to alternately charge each other.

[0039] In one example, referring to FIG. 1 and FIG. 2, the inverter 3 includes an IGBT tube T1, an IGBT tube T2, an IGBT tube T3, an IGBT tube T4, an IGBT tube T5 and an IGBT tube T6. The IGBT tubes T1-T6 form three bridge arms. An insulated gate bipolar transistor (IGBT) is a composite voltage-driven power semiconductor device composed of a bipolar junction transistor (BJT) tube and a metal oxide semiconductor (MOS) tube, and has the advantages of both the high input impedance of a MOSFET (metal oxide semiconductor field effect transistor) and the low on-voltage drop of a giant transistor (GTR). Referring to FIG. 2, in the inverter 3, each IGBT tube is further connected in anti-parallel with a diode, and the diodes VD1-VD6 may protect the circuit. In another embodiment, the IGBT tubes T1-T6 may be alternatively replaced by BJT tubes, respectively. In another embodiment, the IGBT tubes T1-T6 may be alternatively replaced by MOS tubes, respectively. In another embodiment, each of the IGBT tubes T1-T6 may alternatively be replaced with a silicon carbide (SiC) power tube.

[0040] In the embodiment of the present disclosure, referring to FIG. 2, the first controller outputs six driving signals Q1 to Q6. The driving signal Q1 is applied to the IGBT tube T1, the driving signal Q2 is applied to the IGBT tube T2, the driving signal Q3 is applied to the IGBT tube T3, the driving signal Q4 is applied to the IGBT tube T4, the driving signal Q5 is applied to the IGBT tube T5, and the driving signal Q6 is applied to the IGBT tube T6. By applying the driving signals Q1 to Q6 to the IGBT tubes T1 to T6, the first controller alternately turns on the loop between the first battery core group 1 and the AC motor 4 and the loop between the second battery core group 2 and the AC motor 4, so that the first battery core group 1 and the second battery core group 2 alternately charge each other. In one example, the first battery core group 1 is discharged, and the inverter 3 converts the DC current output by the first battery core group 1 into an AC current and inputs the AC current to the AC motor 4. The AC motor 4 stores electrical energy in its coils to charge the second battery core group 2. Then, the second battery core group 2 is discharged, and the inverter 3 converts the DC current output by the second battery core group 2 into AC current and inputs the AC current to the AC motor 4. The AC motor 4 stores electrical energy in its coils to charge the first battery core group 1. The first battery core group 1 and the second battery core group 2 alternately charge each other via the AC motor 4.

[0041] 1 and 2, a switch 5 is provided in the connection line S1, and a switch 6 is provided in the connection line S2. The heating system further includes a second controller 8. The second controller 8 is configured to control the on / off state of the switch 5 and the switch 6, whereby the connection lines S1 and S2 are turned on when the power battery needs to be heated, and the connection lines S1 and S2 are turned off when the power battery does not need to be heated, thereby ensuring the safety of the vehicle and the power battery. For example, the second controller 8 controls the switch 5 and the switch 6 to be off when the electric vehicle is running, thereby ensuring the safety of the vehicle while it is running.

[0042] 1 and 2, in order to improve the safety of the battery heating process, each of the connection lines S1 and S2 is provided with a protection circuit, such as a fuse and a relay.

[0043] In one example, one or more of the multiple connecting lines are connected in series with a load, and the load consumes some energy to prevent the connecting lines from overheating. For example, only the connecting line S1 is connected in series with the load, only the connecting line S2 is connected in series with the load, or each of the connecting lines S1 and S2 is connected in series with the load. The loads connected in series with different connecting lines may have the same or different power.

[0044] 1 further shows a power distribution box of the electric vehicle. The power distribution box mainly distributes power based on the status of the power load of the electric vehicle.

[0045] In one example, the first battery core group 1 and the second battery core group 2 belong to the same battery pack, and the first battery core group 1 and the second battery core group 2 have the same electromotive force. In other words, the second end of the connecting line is connected to an equipotential point of the battery pack. An equipotential point means that the absolute value of the voltage difference from the point to all the positive pole ports of the battery pack is the same as the absolute value of the voltage difference from the point to all the negative pole ports of the battery pack.

[0046] In one example, the first battery core group 1 and the second battery core group 2 belong to the same battery pack, and the first battery core group 1 and the second battery core group 2 have different electromotive forces. In other words, the second end of the connecting line is connected to a non-equipotential point of the battery pack. Non-equipotential point means that the absolute value of the voltage difference from the point to all the positive pole ports of the battery pack is not equal to the absolute value of the voltage difference from the point to all the negative pole ports of the battery pack. As shown in FIG. 1, the battery units included in the first battery core group 1 and the battery units included in the second battery core group 2 are of the same model but different in quantity. Therefore, the first battery core group and the second battery core group have different electromotive forces, and the second end of the connecting line is connected to a non-equipotential point of the battery pack.

[0047] 3 and 4, the power battery includes a first battery core group 1 and a second battery core group 2 connected in series. The heating system includes an inverter 3, an AC motor 4, a first controller, a connection line S3, a connection line S4, a connection line S5, a connection line S6, and a connection line S7.

[0048] 3, first ends of the connection lines S3 to S7 are connected in parallel and then connected to the neutral point N of the AC motor 4, and second ends of the connection lines S3 to S7 are connected in parallel and then connected to the same connection point between the first battery core group 1 and the second battery core group 2. Referring to FIG 4, first ends of the connection lines S3 to S7 are connected in parallel and then connected to the neutral point N of the AC motor 4, and second ends of the connection lines S3 to S7 are connected to different connection points between the first battery core group 1 and the second battery core group 2, respectively.

[0049] 3 and 4, the connection lines S3 to S7 correspond to the same switch 5. The heating system further includes a second controller 8. The second controller 8 is configured to control the switch 5 to simultaneously turn on the connection lines S3 to S7, whereby the connection lines S3 to S7 are turned on when the power battery needs to be heated and turned off when the power battery does not need to be heated, thereby ensuring the safety of the vehicle and the power battery. For example, the second controller 8 controls the switch 5 to be turned off when the electric vehicle is running, thereby ensuring the safety of the vehicle while it is running.

[0050] 3 and 4, the connecting lines S3 to S7 share the same protection circuit, which may be, for example, a fuse or a relay, to improve the safety of the battery heating process.

[0051] Each of the connection lines S3 to S7 is connected in series with a heating load, i.e., a heater as shown in FIG. 3 and FIG. 4. In the embodiment of the present disclosure, the heating load is configured to heat the first battery core group 1 and / or the second battery core group 2. The heating method by which the heating load heats the first battery core group 1 and / or the second battery core group 2 is thermoelectric conversion. Under the influence of the current in the connection lines, the electric energy is converted into thermal energy, causing the heating load to be heated. The heated heating load may conduct heat to the first battery core group 1 and / or the second battery core group 2.

[0052] In the embodiment of the present disclosure, the heating load may be one of a heating film, a heating plate, or a heating wire. The heating load may be one of a resistive heating film, a positive temperature coefficient (PTC) heater, an eddy current heater, a ceramic heater, a silicone rubber heating plate, or another type of heating load. For example, the connecting wire S3 is connected in series with the PTC heater, and the connecting wire S4 is connected in series with the resistive heating film.

[0053] In one example, a heating load may be attached to a surface of the first battery core group 1 and / or the second battery core group 2 to heat the first battery core group 1 and / or the second battery core group 2.

[0054] In the embodiment of the present disclosure, the first battery core group 1 and the second battery core group 2 may each be formed by stacking a plurality of battery core units. The battery unit may be a single battery or a battery module. The stack may be arranged in the thickness direction of the battery core unit, or in the length direction or width direction of the battery core unit.

[0055] In one example, the heating load is disposed on the second surface of the first battery core group 1 and / or the second surface of the second battery core group 2. The second surface of the first battery core group 1 is a surface of at least one battery core unit in the first battery core group 1, and the second surface of the second battery core group 2 is a surface of at least one battery core unit in the second battery core group 2. In one example, the second surface may be a surface of a battery core unit in the battery core group.

[0056] For example, if the battery unit is blade-shaped, the heating load may be attached to the upper or lower surface of the battery core unit. For example, if the battery unit is square-shaped, the heating load may be attached to any surface of the battery core unit. For example, if the battery unit is cylindrical, the battery unit has three surfaces including two circular end surfaces and one curved surface, and the heating load may be attached to the curved surface.

[0057] In other embodiments, the second surface may also refer to the opposing surfaces of two adjacent battery core units.

[0058] In one example, the heating load is disposed on a first surface of the first battery core group 1 and / or a first surface of the second battery core group 2. The first surface of the first battery core group 1 is a surface formed by stacking the battery core units in the first battery core group 1, and the first surface of the second battery core group 2 is a surface formed by stacking the battery core units in the second battery core group 2. This embodiment allows the heating load to approach multiple battery core units in the battery core group simultaneously, making it easier to heat multiple battery core units in the first battery core group 1 simultaneously, and achieving a more uniform heating effect. The surface formed by stacking may be in the left-right direction or the up-down direction.

[0059] For example, referring to FIG. 5, the first battery core group 1 is formed by stacking a plurality of blade-shaped battery core units. The battery core units are stacked to form a stacking surface 101 and a stacking surface 102. The heating load is disposed on the stacking surface 101 or the stacking surface 102. For example, referring to FIG. 6, the second battery core group 2 is formed by stacking a plurality of cylindrical battery core units. The circular end surfaces of the two sides of the plurality of battery core units respectively form the stacking surfaces, and the heating load is disposed on the stacking surfaces. Alternatively, the middle curved surfaces of the plurality of battery core units form the stacking surfaces, and the heating load is disposed on the stacking surfaces.

[0060] In one example, the battery core units are stacked in the same direction to form multiple first surfaces, and the heating load is placed on the first surface with a larger area, which may facilitate the design and layout of the heating load. For example, the heating load is placed on the first surface with a larger area. When the load power is the same, a heating load in the form of a heating film may be selected. Because the contact area of ​​the heating film is larger, the battery core group is heated more uniformly.

[0061] In one example, the heating load is disposed corresponding to the center of the battery core unit. When the battery is heated through the excitation current, the current density distribution in the battery core unit becomes non-uniform, which tends to cause a large temperature difference in the battery core unit. The temperature is relatively high at both ends of the battery core unit and relatively low in the center. The heating load is disposed corresponding to the center of the battery core unit to selectively locally heat the low temperature region of the battery core unit, thereby greatly reducing the temperature difference in different regions of the battery core unit and enhancing the uniformity of the overall temperature distribution.

[0062] In one example, the heating load corresponds to a low temperature region of the first battery core group 1 and / or the second battery core group 2. The low temperature region of the battery core group is a region where the temperature of the surface of the battery core group is lower than a first preset value. For example, the first preset value is 10 degrees Celsius. The first preset value may correspond to a range. For example, the range is 10 degrees Celsius to 15 degrees Celsius. The first preset value is set within a range based on the operating conditions. In one example, the low temperature region of the battery core group is a target region, and the temperature of the target region is lower than the first preset value and is lower than the temperature of the high temperature region of the battery core group by at least a second preset value. For example, the second preset value is 5 degrees Celsius.

[0063] For example, referring to FIG. 5, the first battery core group 1 is formed by stacking a plurality of blade-shaped battery core units. The battery core units are stacked to form a stacking surface 101 and a stacking surface 102. A heating load is disposed on the stacking surface 101 or the stacking surface 102, and the heating load corresponds to the center of the battery core unit. In one example, the stacking surface 102 has a larger area. The heating load is disposed on the stacking surface 102, and the heating load corresponds to the center of the battery core unit.

[0064] In one example, the material of the wires used to connect the circuits may be a metal with good electrical conductivity, such as copper or aluminum, or a carbon-based material with good electrical conductivity.

[0065] In one example, one connection line may be connected in series with one heating load. The form, type and heating efficiency of the heating load may be flexibly designed based on the actual requirements. The specific arrangement position of the heating load may also be flexibly designed based on the space environment and heating requirements. Based on the results of actual testing or simulation experiments, device selection and layout may be made for the heating load. In one example, one connection line is connected in series with multiple heating loads. The form, type and heating efficiency of the multiple heating loads may be the same or different. The specific quantity and distribution position of the multiple heating loads may be flexibly designed based on the space environment and heating requirements. Based on the results of actual testing or simulation experiments, device selection and layout may be made for the heating load.

[0066] In one example, each of the at least two or more heating wires is connected in series with one heating load. In one example, the form, type and heating efficiency of the heating loads may be the same or different. In one example, the specific quantity and distribution position of the heating loads may be flexibly designed based on the space environment and heating requirements. In one example, the selection and layout of the devices may be made for the heating load based on the results of actual testing or simulation experiments.

[0067] According to the heating system for power battery provided in the embodiment of the present disclosure, a connection line is added to the original circuit topology structure of the electric vehicle. The connection line is from the neutral point of the AC motor to the connection point between the first battery core group and the second battery core group, which requires little modification to the original circuit of the electric vehicle, and the solution is simple and easy to implement.

[0068] According to the heating system for power battery provided in the embodiment of the present disclosure, the upper bridge arm and the lower bridge arm of the inverter are used in time division, so that the three inductance coils of the motor can be used extensively to generate AC pulse current to rapidly heat the two battery core groups.

[0069] During heating of the power battery, the frequency and magnitude of the charge / discharge current, i.e., the excitation current, are limited by related factors. The heating system provided in the embodiment of the present disclosure can slightly limit the excitation current, allowing batteries with large excitation currents to be heated. In the self-heating condition of a conventional battery pack, the maximum current of the inverter is limited to the minimum current among the withstand currents of the IGBT tubes T1 to T6. However, in the embodiment of the present disclosure, the maximum current of the inverter is limited to the sum of the withstand currents of the IGBT tubes T1, T2, and T3, and the sum of the withstand currents of the IGBT tubes T4, T5, and T6.

[0070] The heating system for power battery in the embodiment of the present disclosure includes multiple connecting wires. The multiple connecting wires share an excitation current, which reduces the current on a single connecting wire and improves the safety of the heating system. Compared with the design of only one connecting wire at the same heating efficiency, the design of multiple connecting wires can prevent the current on a single connecting wire from being excessive, which can prevent the connecting wire from burning due to excessive current, thereby improving the safety of the heating system.

[0071] Multiple connecting lines may act as redundant backups for each other. The failure of one connecting line will not affect the normal operation of the other connecting lines, and the power battery can still be heated, which greatly improves the safety and stability of the self-heating system.

[0072] Furthermore, since a single connecting wire needs to carry a small amount of excitation current, the requirements for the material and radius of the connecting wire are reduced, which is beneficial to reducing the cost of the heating system.

[0073] The first controller in the embodiment of the present disclosure may include a processor, a memory, and a program or instruction stored in the memory and executable on the processor, the program or instruction being executed by the processor to implement self-heating of the power battery.

[0074] An embodiment of the present disclosure provides an electric vehicle, as shown in Figure 7, the electric vehicle includes a heating system for a power battery according to any one of the previous embodiments.

[0075] All embodiments herein are described in an inventive manner. Cross references may be made to the same or similar parts of the embodiments. Each embodiment focuses on the differences from the other embodiments. In the electric vehicle embodiment, please refer to the partial description of the heating system embodiment for the relevant parts.

[0076] The embodiments of the present specification have been described above. The above description is illustrative but not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terms used in this specification are selected to best describe the principles of the embodiments, practical applications or improvements of the technology in the market, or to enable those skilled in the art to understand the embodiments disclosed in this specification.

Claims

1. A heating system for a power battery, the power battery comprising a first battery core group (1) and a second battery core group (2) connected in series, the heating system comprising an inverter (3), an AC motor (4), a first controller (7), and a plurality of connecting lines; The inverter (3) has three bridge arms, the positive pole of the power battery is connected to the upper bridge arm of the inverter (3), the negative pole of the power battery is connected to the lower bridge arm of the inverter (3), the midpoints of the three bridge arms of the inverter (3) are respectively connected to the tips of the three-phase coils of the AC motor (4), and the ends of the AC motor (4) are connected to each other to form a neutral point; a first end of the connection line is connected to the neutral point of the AC motor (4), and a second end of the connection line is connected to a connection point between the first battery core group (1) and the second battery core group (2); The first controller (7) is configured to input a drive signal to the inverter (3); the first battery core group (1), the second battery core group (2), the inverter (3), the AC motor (4) and the connecting wires form an AC self-heating loop; Heating system for power batteries.

2. A switch is provided for each of the plurality of connection lines, or the plurality of connection lines correspond to the same switch; The heating system includes a second controller (8), the second controller (8) being configured to control the switch to turn the connecting line on and off. The heating system of claim 1 .

3. The heating system according to claim 1 , wherein each of the plurality of connecting lines is provided with a protection circuit, or the plurality of connecting lines share a protection circuit.

4. The heating system according to claim 1 , wherein at least one of the plurality of connecting lines is connected in series with at least one load.

5. The heating system according to any one of claims 1 to 4, wherein the at least one load includes a heating load, the heating load configured to heat the first battery core group (1) and / or the second battery core group (2).

6. The heating system according to any one of claims 1 to 5, wherein the heating load is attached to a surface of the first battery core group (1) and / or a surface of the second battery core group (2).

7. 7. The heating system according to claim 1, wherein the heating load is arranged on a first surface of the first battery core group (1) and / or a first surface of the second battery core group (2), the first surface of the first battery core group (1) is a surface formed by stacking battery core units in the first battery core group (1), and the first surface of the second battery core group (2) is a surface formed by stacking battery core units in the second battery core group (2).

8. The heating system according to any one of claims 1 to 7, wherein the heating load is arranged on a second surface of the first battery core group (1) and / or a second surface of the second battery core group (2), the second surface of the first battery core group (1) being a surface of at least one battery core unit in the first battery core group (1), and the second surface of the second battery core group (2) being a surface of at least one battery core unit in the second battery core group (2).

9. 9. The heating system according to claim 1, wherein the heating load corresponds to a low temperature area of ​​the first battery core group (1) and / or the second battery core group (2), the low temperature area being an area where the temperature of the surface of the battery core group is lower than a first preset value.

10. An electric vehicle comprising a heating system according to any one of claims 1 to 9.

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