# Patent

## Title
Circuits and methods for heating batteries in parallel using resonance components in series

## Abstract

Circuit and method for heating first and second batteries. The heating circuit includes first and second switch units, first and second damping components, first and second current storage components, switching control module and energy storage component. The first battery, first damping and current storage components, energy storage component and first switch unit are connected in a first loop to constitute a first charging/discharging circuit. The second battery, second damping and current storage components, energy storage component and second switch unit are connected in a second loop to constitute a second charging/discharging circuit. When the energy storage component is charged/discharged, current in the second charging/discharging circuit is reverse to current in the first charging/discharging circuit. The switching control module controls the first and second switch units to switch on in alternate, so as to control electric energy to flow among the first battery, energy storage component and second battery.

## Background
1. CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to Chinese Patent Application No. 201010245288.0, filed Jul. 30, 2010, Chinese Patent Application No. 201010274785.3, filed Aug. 30, 2010, Chinese Patent Application No. 201010603669.1, filed Dec. 23, 2010, and Chinese Patent Application No. 201010604677.8, filed Dec. 23, 2010, all these four applications being incorporated by reference herein for all purposes.
Additionally, this application is related to International Application Publication No. WO2010/145439A1 and Chinese Application Publication No. CN102055042A, both these two applications being incorporated by reference herein for all purposes.
2. BACKGROUND OF THE INVENTION
The present invention pertains to electric and electronic field, in particular related to a battery heating circuit.
Considering cars need to run under complex road conditions and environmental conditions or some electronic devices are used under harsh environmental conditions, the battery, which serves as the power supply unit for electric-motor cars or electronic devices, need to be adaptive to these complex conditions. In addition, besides these conditions, the service life and charge/discharge cycle performance of the battery need to be taken into consideration; especially, when electric-motor cars or electronic devices are used in low temperature environments, the battery needs to have outstanding low-temperature charge/discharge performance and higher input/output power performance.
Usually, under low temperature conditions, the resistance of the battery will increase, and so will the polarization; therefore, the capacity of the battery will be reduced.
To keep the capacity of the battery and improve the charge/discharge performance of the battery under low temperature conditions, some embodiments of the present invention provide a battery heating circuit.
3. BRIEF SUMMARY OF THE INVENTION
The objective of certain embodiments of the present invention is to provide a battery heating circuit, in order to solve the problem of decreased capacity of the battery caused by increased resistance and polarization of the battery under low temperature conditions.
Certain embodiments of the present invention provide a battery heating circuit, wherein: the battery comprises a first battery and a second battery; the heating circuit comprises a first switch unit, a second switch unit, a damping component R1, a damping component R2, a current storage component L3, a current storage component L4, a switching control module and an energy storage component V1; the first battery, damping component R1, current stage component L3, energy storage component V1 and first switch unit are connected in series to constitute a first charging/discharging circuit; the second battery, damping component R2, current stage component L4, energy storage component V1 and second switch unit are connected in series to constitute a second charging/discharging circuit; when the energy storage component V1 is charged or discharges, the direction of charging/discharging current in the second charging/discharging circuit is reverse to the direction of charging/discharging current in the first charging/discharging circuit; the switching control module is electrically connected with the first switch unit and second switch unit, and is configured to control the first switch unit and second switch unit to switch on in alternate, so as to control the electric energy to flow among the first battery, energy storage component V1 and second battery.
In the heating circuit provided in certain embodiments of the present invention, the first switch unit and second switch unit can be controlled by the switching control module to switch on in alternate, so that the electric energy can flow back-and-forth among the first battery, energy storage component V1 and second battery in alternate, and thereby causes the damping component R1 and damping component R2 to generate heat, so as to heat up the first battery and second battery. Since the direction of charging/discharging current in the second charging/discharging circuit is reverse to the direction of charging/discharging current in the first charging/discharging circuit when viewed from the aspect of the energy storage component V1, the energy charged from the first battery into the energy storage component V1 can be transferred successfully to the second battery, so that the heating efficiency is improved.
Other characteristics and advantages of the present invention will be further described in detail in the following section for embodiments.



4. BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, as a part of this description, are provided here to facilitate further understanding of the present invention, and are used in conjunction with the following embodiments to explain the present invention, but shall not be comprehended as constituting any limitation on the present invention. In the figures:
FIG. 1 is a schematic diagram of the heating circuit in the first embodiment of the present invention;
FIG. 2 is a schematic diagram of a heating circuit in the first embodiment of the present invention;
FIG. 3 is a timing sequence diagrams of waveform of the heating circuit in FIG. 2;
FIG. 4 is a schematic diagram of another heating circuit in the first embodiment of the present invention;
FIG. 5 is a timing sequence diagrams of waveform of the heating circuit in FIG. 4;
FIG. 6 is a schematic diagram of the heating circuit in the second embodiment of the present invention;
FIG. 7 is a schematic diagram of a heating circuit in the second embodiment of the present invention;
FIG. 8 is a timing sequence diagrams of waveform of the heating circuit in FIG. 7;
FIG. 9 is a schematic diagram of another heating circuit in the second embodiment of the present invention;
FIG. 10 is a timing sequence diagrams of waveform of the heating circuit in FIG. 9; and
FIG. 11 is a circuit diagram of one embodiment of the first and/or second switch unit in the heating circuit provided in the present invention.



5. DETAILED DESCRIPTION OF THE INVENTION
Certain embodiments of the present invention are described in detail below, with reference to the accompanying drawings. It should be appreciated that the embodiments described here are only provided to describe and explain the present invention, but shall not be deemed as constituting any limitation on the present invention.
It is noted that, unless otherwise specified, when mentioned hereafter in this description, the term “switching control module” may refer to any controller that can output control commands (e.g., pulse waveforms) under preset conditions or at preset times and thereby control the switch unit connected to it to switch on or switch off accordingly, according to some embodiments. For example, the switching control module can be a PLC. Unless otherwise specified, when mentioned hereafter in this description, the term “switch” may refer to a switch that enables ON/OFF control by using electrical signals or enables ON/OFF control on the basis of the characteristics of the component according to certain embodiments. For example, the switch can be either a one-way switch (e.g., a switch composed of a two-way switch and a diode connected in series, which can be conductive in one direction) or a two-way switch (e.g., a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) or an IGBT with an anti-parallel freewheeling diode). Unless otherwise specified, when mentioned hereafter in this description, the term “two-way switch” may refer to a switch that can be conductive in two directions, which can enable ON/OFF control by using electrical signals or enable ON/OFF control on the basis of the characteristics of the component according to some embodiments. For example, the two-way switch can be a MOSFET or an IGBT with an anti-parallel freewheeling diode. Unless otherwise specified, when mentioned hereafter in this description, the term “one-way semiconductor component” may refer to a semiconductor component that can be conductive in one direction, such as a diode, according to certain embodiments. Unless otherwise specified, when mentioned hereafter in this description, the term “charge storage component” may refer to any device that can enable charge storage, such as a capacitor, according to some embodiments. Unless otherwise specified, when mentioned hereafter in this description, the term “current storage component” may refer to any device that can store current, such as an inductor, according to certain embodiments. Unless otherwise specified, when mentioned hereafter in this description, the term “forward direction” may refer to the direction in which the energy flows from the battery to the energy storage circuit, and the term “reverse direction” may refer to the direction in which the energy flows from the energy storage circuit to the battery, according to some embodiments. Unless otherwise specified, when mentioned hereafter in this description, the term “battery” may comprise primary battery (e.g., dry battery or alkaline battery, etc.) and secondary battery (e.g., lithium-ion battery, nickel-cadmium battery, nickel-hydrogen battery, or lead-acid battery, etc.), according to certain embodiments. Unless otherwise specified, when mentioned hereafter in this description, the term “damping component” may refer to any device that inhibits current flow and thereby enables energy consumption, such as a resistor, etc., according to some embodiments. Unless otherwise specified, when mentioned hereafter in this description, the term “main loop” may refer to a loop composed of battery, damping component, switch unit and energy storage circuit connected in series according to certain embodiments.
It should be noted specially that, considering different types of batteries have different characteristics, in some embodiments of the present invention, “battery” may refer to an ideal battery that does not have internal parasitic resistance and parasitic inductance or has very low internal parasitic resistance and parasitic inductance, or may refer to a battery pack that has internal parasitic resistance and parasitic inductance; therefore, those skilled in the art should appreciate that if the battery is an ideal battery that does not have internal parasitic resistance and parasitic inductance or has very low internal parasitic resistance and parasitic inductance, the damping component R1 may refer to a damping component external to the battery and the current storage component L1 may refer to a current storage component external to the battery; if the battery is a battery pack that has internal parasitic resistance and parasitic inductance, the damping component R1 may refer to a damping component external to the battery or refer to the parasitic resistance in the battery pack, and the current storage component L1 may refer to a current storage component external to the battery or refer to the parasitic inductance in the battery pack, according to certain embodiments.
To ensure the normal service life of the battery, according to some embodiments, the battery can be heated under low temperature condition, which is to say, when the heating condition is met, the heating circuit is controlled to start heating for the battery; when the heating stop condition is met, the heating circuit is controlled to stop heating, according to certain embodiments.
In the actual application of battery, the battery heating condition and heating stop condition can be set according to the actual ambient conditions, to ensure normal charge/discharge performance of the battery, according to some embodiments.
FIG. 1 is a schematic diagram of the heating circuit in the first embodiment of the present invention. As shown in FIG. 1, one embodiment of the present invention provides a battery heating circuit, wherein: the battery comprises a first battery E1 and a second battery E2; the heating circuit comprises a first switch unit 10, a second switch unit 20, a damping component R1, a damping component R2, a current stage component L3, a current stage component L4, a switching control module 100 and an energy storage component V1; the first battery E1, damping component R1, current stage component L3, energy storage component V1 and first switch unit 10 are connected in series to constitute a first charging/discharging circuit; the second battery E2, damping component R2, current stage component L4, energy storage component V1 and second switch unit 20 are connected in series to constitute a second charging/discharging circuit; when the energy storage component V1 is charged or discharges, the direction of charging/discharging current in the second charging/discharging circuit is reverse to the direction of charging/discharging current in the first charging/discharging circuit; the switching control module 100 is electrically connected with the first switch unit 10 and second switch unit 20, and is configured to control the first switch unit 10 and second switch unit 20 to switch on in alternate, so as to control the electric energy to flow among the first battery E1, energy storage component V1 and second battery E2.
wherein: the damping component R1 and the damping component R2 can be the parasitic resistances in the first battery E1 and the second battery E2 respectively, and the current storage component L3 and the current storage component L4 can be the parasitic inductances in the first battery E1 and the second battery E2 respectively.
Wherein: the energy storage component V1 can be an inductor L1 or a capacitor C1. FIG. 2 and FIG. 4 show the circuit diagrams in the case that the energy storage component V1 is an inductor L1 or capacitor C1, respectively; FIG. 3 and FIG. 5 show the timing sequence diagrams of waveform corresponding to FIG. 2 and FIG. 4, respectively. Hereunder the heating circuit in the first embodiment of the present invention will be described, with reference to FIG. 2 to FIG. 5.
As shown in FIG. 2, the energy storage component V1 can be an inductor L1, the switching control module 100 can control the first switch unit 10 and second switch unit 20 to switch theirs ON/OFF states when the current in the inductor L1 reaches a preset value, for example, the first switch unit 10 switches from ON state to OFF state, while the second switch unit 20 switches from OFF state to ON state, so that the electric energy stored in the inductor L1 from one battery can flow into the other battery. As the electric energy flows, current is generated; by keeping current flowing through the damping component R1 and damping component R2 continuously, the damping component R1 and damping component R2 generate heat, and thereby heat up the first battery E1 and second battery E2.
FIG. 3 is a timing sequence diagram of the waveform of the circuit shown in FIG. 2. Hereunder the working process of the heating circuit provided in one embodiment of the present invention will be described, with reference to FIG. 3. First, the switching control module 100 controls the first switch unit 10 to switch on, and controls the second switch unit 20 to switch off; thus, the first battery E1 charges the inductor L1, and therefore the current in the inductor L1 increases gradually (as indicated by the time period t1 shown in FIG. 3). When the current IL1 in the inductor L1 rises to a preset value, the switching control module 100 controls the first switch unit 10 to switch off and controls the second switch unit 20 to switch on; the inductor L1 transfers the energy charged in it to the second battery E2, and therefore the current in the inductor L1 decreases slowly (as indicated by the time period t2). Then, after the energy in the inductor L1 is released, the second battery E2 starts charging the inductor L1, and therefore the current IL1 in the inductor L1 increases slowly. At this time, the flow direction of the current IL1 in the inductor L1 is reverse to the flow direction in the time period t1 and t2 (as indicated by the time period t3). Then, when the current IL1 in the inductor L1 rises to a preset value, the switching control module 100 controls the first switch unit 10 to switch on and controls the second switch unit 20 to switch off; the inductor L1 transfers the energy charged in it to the first battery E1, and therefore the current IL1 in the inductor L1 decreases slowly (as indicated by the time period t4; now, the heating circuit has accomplished a complete working cycle). In that way, the cycles continue on and on, so that the current flows through damping component R1 and damping component R2 continuously; as a result, the damping component R1 and damping component R2 generate heat, and thereby heat up the first battery E1 and second battery E2 to the expected condition. It should be noted: UL1 in FIG. 3 represents the voltage of the inductor L1, which is a constant value in forward direction when the current IL1 through the inductor L1 increases in forward direction or decreases in reverse direction, and is a constant value in reverse direction when the current IL1 through the inductor L1 decreases in forward direction or increases in reverse direction.
In the above working process of the heating circuit provided in one embodiment of the present invention, the current can be kept flowing back-and-forth between the first battery E1 and the second battery E2, so that the two batteries are heated up in alternate, and therefore the heating efficiency is improved. In addition, owing to the existence of the inductor L1, the current flowing through the first and second batteries and the first and second switch units is limited; alternatively, the current flowing through the first and second batteries and the first and second switch units can be limited by using the preset value, so as to reduce the current flowing through the first and second batteries and the first and second switch units, to attain the purpose of protecting the first and second batteries and the first and second switch units.
As shown in FIG. 4, the energy storage component V1 is a capacitor C1, the switching control module 100 can control the first switch unit 10 and second switch unit 20 to switch their ON/OFF states when the current in the capacitor C1 reaches zero after each pair of continuous positive and negative half cycles or each pair of continuous negative and positive half cycles, for example, the first switch unit 10 can switch from ON state to OFF state, while the second switch unit 20 can switch from OFF state to ON state, so that the electric energy stored in the capacitor C1 from one battery can flow into the other battery. As the electric energy flows, current is generated; by keeping current flowing through the damping component R1 and damping component R2 continuously, the damping component R1 and damping component R2 generate heat, and thereby heat up the first battery E1 and second battery E2.
FIG. 5 is a timing sequence diagram of the waveform of the circuit shown in FIG. 4. Hereunder the working process of the heating circuit provided in one embodiment of the present invention will be described, with reference to FIG. 5. First, the switching control module 100 controls the first switch unit 10 to switch on, and controls the second switch unit 20 to switch off; the first battery E1, damping component R1, current stage component L3, capacitor C1 and first switch unit 10 form a charging/discharging circuit, which performs charging/discharging operations (as indicated by the time period t1 in FIG. 5). After the charging/discharging circuit completes a charging/discharging cycle (at this point, the current IC1 through the capacitor C1 reaches zero after the negative half cycle, the voltage UC1 of the capacitor C1 has passed the peak value in the positive half cycle), the switching control module 100 controls the first switch unit 10 to switch off and controls the second switch unit 20 to switch on; thus, the second battery E2, damping component R2, current stage component L4, capacitor C1 and second switch unit 20 form a charging/discharging circuit, which performs charging/discharging operations (as indicated by the time period t2 in FIG. 5). After the charging/discharging circuit completes a charging/discharging cycle (at this point, the current IC1 through capacitor C1 reaches zero after the positive half cycle, and the entire heating circuit accomplishes a complete working cycle), the switching control module 100 controls the first switch unit 10 to switch on and controls the switch unit 20 to switch off again; in that way, the cycles continue on, so that the current flows through the damping component R1 and damping component R2 continuously; as a result, the damping component R1 and damping component R2 generate heat, and thereby heat up the first battery E1 and second battery E2 to the expected condition.
In the above working process of the heating circuit shown in FIG. 4, the current can be kept flowing back-and-forth between the first battery E1 and the second battery E2, so that the two batteries are heated up in alternate, and therefore the heating efficiency is improved. In addition, in the heating circuit shown in FIG. 4, the capacitor is connected in series with the battery. When the battery is heated, safety problems related with failure or short circuit of the switch unit can be avoided owing to the existence of the serially connected capacitor, and therefore the battery can be protected effectively.
FIG. 6 is a schematic diagram of the heating circuit in the second embodiment of the present invention. Preferably, as shown in FIG. 6, the heating circuit provided in one embodiment of the present invention can further comprise an energy storage component V2; the first battery E1, damping component R1, current stage component L3, energy storage component V2 and second switch unit 20 are connected in series to form a third charging/discharging circuit; the second battery E2, damping component R2, current stage component L4, energy storage component V2 and first switch unit 10 are connected in series to form a fourth charging/discharging circuit; when the energy storage component V2 is charged or discharges, the direction of charging/discharging current in the third charging/discharging circuit is reverse to the direction of charging/discharging current in the fourth charging/discharging circuit; the switching control module 100 also controls the electric energy to flow among the first battery E1, energy storage component V1, energy storage component V2 and second battery E2 by controlling the first switch unit 10 and second switch unit 20 to switch on in alternate.
Wherein: the energy storage component V2 can also be an inductor L2 or a capacitor C2. FIG. 7 and FIG. 9 show the circuit diagrams in the case that the energy storage component V2 is an inductor L2 or capacitor C2, respectively; FIG. 8 and FIG. 10 show the timing sequence diagrams of waveform corresponding to FIG. 7 and FIG. 9, respectively. Hereunder the heating circuit in the second embodiment of the present invention will be described, with reference to FIG. 7 to FIG. 10.
As shown in FIG. 7, the energy storage component V1 is an inductor L1, the energy storage component V2 is an inductor L2, the switching control module can control the first switch unit 10 and second switch unit 20 to switch their ON/OFF states when the current in the inductor L1 or inductor L2 reaches a preset value. FIG. 8 is a timing sequence diagram of the waveform of the circuit shown in FIG. 7. Hereunder the working process of the heating circuit provided in the second embodiment of the present invention will be described, with reference to FIG. 8.
First, the switching control module 100 controls the first switch unit 10 to switch on, and controls the second switch unit 20 to switch off; thus, the first battery E1 charges the inductor L1, and the second battery E2 charges the inductor L2; as a result, the current IL1 and current IL2 in the inductor L1 and inductor L2 increase slowly (as indicated by the time period t1 shown in FIG. 8). When the current IL1 in the inductor L1 or the current IL2 in the inductor L2 rises to a preset value, the switching control module 100 controls the first switch unit 10 to switch off and controls the second switch unit 20 to switch on; the inductor L1 transfers the energy stored in it to the second battery E2, and the inductor L2 transfers the energy stored in it to the first battery E1; therefore the current IL1 in the inductor L1 and the current IL2 in the inductor L2 decrease slowly (as indicated by the time period t2). Then, after the energy in the inductor L1 and L2 is released, the second battery E2 turns to charge the inductor L1, and the first battery E1 turns to charge the inductor L2; therefore the current IL1 in the inductor L1 and the current IL2 in the inductor L2 increase slowly. At this time, the flow direction of the current in the inductor L1 and L2 is reverse to the flow direction in the time period t1 and t2 (as indicated by the time period t3). Then, when the current IL1 in the inductor L1 or the current IL2 in the inductor L2 rises to a preset value, the switching control module 100 controls the first switch unit 10 to switch on and controls the second switch unit 20 to switch off; the inductor L1 transfers the energy stored in it to the first battery E1, and the inductor L2 transfers the energy stored in it to the second battery E2; therefore the current IL1 in the inductor L1 and the current IL2 in the inductor L2 decrease slowly (as indicated by the time period t4; now, the heating circuit has accomplished a complete working cycle). The cycles continue on and on, till the first battery E1 and second battery E2 are heated up satisfactorily. It should be noted: UL1 and UL2 in FIG. 8 represent the voltage of the inductor L1 and the voltage of the inductor L2; the voltage UL1 is a constant value in forward direction when the current IL1 through the inductor L1 increases in forward direction or decreases in reverse direction, and is a constant value in reverse direction when the current IL1 through the inductor L1 decreases in forward direction or increases in reverse direction. The same is true also for voltage UL2.
By adding an inductor L2 in the heating circuit, the first battery E1 and second battery E2 are always in a charging/discharging process, and current always flows through the impedance component R1 and impedance component R2; thus, the heating efficiency is further improved. Alternatively, the current flowing through the first and second batteries and the first and second switch units can be limited by the inductor L1 and L2 and the preset value, so that the first and second batteries and the first and second switch units are protected.
In addition, it should be noted: the “preset value” mentioned above shall be set according to the current endurable by the first battery E1, second battery E2, and other components/components in the heating circuit, with comprehensive consideration of heating efficiency and protection of the first battery E1 and second battery E2 against damages, as well as the size, weight and cost of the heating circuit.
As shown in FIG. 9, the energy storage component V1 is a capacitor C1, the energy storage component V2 is a capacitor C2, the switching control module 100 can control the first switch unit 10 and second switch unit 20 to switch their ON/OFF states when the current in the capacitor C1 or capacitor C2 reaches zero after each pair of continuous positive and negative half cycles or each pair of continuous negative and positive half cycles. FIG. 10 is a timing sequence diagram of the waveform of the circuit shown in FIG. 9. Hereunder the working process of another heating circuit in the second embodiment of the present invention will be described, with reference to FIG. 9 and FIG. 10.
First, the switching control module 100 controls the first switch unit 10 to switch on, and controls the second switch unit 20 to switch off; the first battery E1, damping component R1, current stage component L3, capacitor C1 and first switch unit 10 form a charging/discharging circuit; the second battery E2, damping component R2, current stage component L4, capacitor C2 and first switch unit 10 form another charging/discharging circuit; the two charging/discharging circuits perform charging/discharging operations (as indicated by the time period t1 shown in FIG. 10; please note: the voltage waveform and current waveform of capacitor C1 are the same as those of the capacitor C2). After the two charging/discharging circuits complete a charging/discharging cycle (at this point, the current IC1 through the capacitor C1 or the current IC2 through the capacitor C2 reaches zero after the negative half cycle, the voltage UC1 of the capacitor C1 or the voltage UC2 of the capacitor C2 has passed the peak value in the positive half cycle), the switching control module 100 controls the first switch unit 10 to switch off and controls the second switch unit 20 to switch on; thus, the first battery E1, damping component R1, current stage component L3, capacitor C2 and second switch unit 20 form a charging/discharging circuit, and the second battery E2, damping component R2, current stage component L4, capacitor C1 and second switch unit 20 form another charging/discharging circuit; the two charging/discharging circuits perform charging/discharging operations (as indicated by the time period t2 shown in FIG. 10; please note: at this point, the voltage waveform and current waveform of the capacitor C1 are the same as those of the capacitor C2). After the two charging/discharging circuits complete a charging/discharging cycle (at this point, the current IC1 through the capacitor C1 or the current IC2 through the capacitor C2 reaches zero after the positive half cycle, and the entire heating circuit accomplishes a complete working cycle), the switching control module 100 controls the first switch unit 10 to switch on and controls the second switch unit 20 to switch off again; in that way, the cycles continue on and on, so that the current flows through the damping component R1 and damping component R2 continuously; thus, the damping component R1 and damping component R2 generate heat, and thereby heat up the first battery E1 and second battery E2 to the expected condition.
By adding a capacitor C2 in the heating circuit, two charging/discharging circuits are formed at the same time in each working cycle, and therefore the first battery E1 and second battery E2 are always in a charging/discharging process, and the current always flows through the damping component R1 and damping component R2; thus, the heating time can be shortened.
FIG. 11 is a circuit diagram of one embodiment of the switch unit in the heating circuit provided in the present invention. As shown in FIG. 11, the first switch unit 10 and/or the second switch unit 20 can comprise a switch K11 and a one-way semiconductor component D11 connected in parallel with the switch K11 in reverse direction, wherein: the switching control module 100 is electrically connected with the switch K11, and is configured to control ON/OFF of the forward direction branches of the first switch unit 10 and/or the second switch unit 20 by controlling ON/OFF of the switch K11. The ON/OFF control of switch K11 can be performed in the grid zone shown in FIG. 3, FIG. 5, FIG. 8 and FIG. 10. In FIG. 5 and FIG. 10, when or after the current flowing through the first switch unit 10 or the second switch unit 20 reaches zero, the switching control module 100 can control the first switch unit 10 or the second switch unit 20 to switch off respectively.
For example, some or all components of various embodiments of the present invention each are, individually and/or in combination with at least another component, implemented using one or more software components, one or more hardware components, and/or one or more combinations of software and hardware components. In another example, some or all components of various embodiments of the present invention each are, individually and/or in combination with at least another component, implemented in one or more circuits, such as one or more analog circuits and/or one or more digital circuits.
While some embodiments of the present invention are described above with reference to the accompanying drawings, the present invention is not limited to the details of those embodiments. Those skilled in the art can make modifications and variations, without departing from the spirit of the present invention. However, all these modifications and variations shall be deemed as falling into the scope of the present invention.
In addition, it should be noted that the specific technical features described in the above embodiments can be combined in any appropriate way, provided that there is no conflict. To avoid unnecessary repetition, certain possible combinations are not described specifically. Moreover, the different embodiments of the present invention can be combined as needed, as long as the combinations do not deviate from the spirit of the present invention. However, such combinations shall also be deemed as falling into the scope of the present invention.
Hence, although specific embodiments of the present invention have been described, it will be understood by those of skill in the art that there are other embodiments that are equivalent to the described embodiments. Accordingly, it is to be understood that the invention is not to be limited by the specific illustrated embodiments, but only by the scope of the appended claims.

## Claims

1. A heating circuit for a battery comprising a first battery and a second battery, the heating circuit comprising a first switch unit, a second switch unit, a first damping component, a second damping component, a first current storage component, a second current storage component, a switching control module and a first energy storage component, wherein:
the first battery, the first damping component, the first current storage component, the first energy storage component and the first switch unit are connected in a first loop to constitute a first charging/discharging circuit;
the second battery, the second damping component, the second current storage component, the first energy storage component and the second switch unit are connected in a second loop to constitute a second charging/discharging circuit;
when the first energy storage component is charged or discharges, a direction of a charging/discharging current in the second charging/discharging circuit is reverse to a direction of a charging/discharging current in the first charging/discharging circuit; and
the switching control module is electrically connected with the first switch unit and the second switch unit, and the switching control module is configured to control the first switch unit and the second switch unit to switch on in alternate, so as to control electric energy to flow among the first battery, the first energy storage component and the second battery.

2. The heating circuit according to claim 1, wherein the first damping component and the second damping component are parasitic resistances in the first battery and the second battery respectively, and the first current storage component and the second current storage component are parasitic inductances in the first battery and the second battery respectively.

3. The heating circuit according to claim 1, wherein the first energy storage component is an inductor.

4. The heating circuit according to claim 3, wherein the switching control module is configured to control the first switch unit and the second switch unit to switch their ON/OFF states when a current in the inductor reaches a preset value.

5. The heating circuit according to claim 1, wherein the first energy storage component is a capacitor.

6. The heating circuit according to claim 1, wherein the heating circuit further comprises a second energy storage component;
the first battery, the first damping component, the first current storage component, the second energy storage component and the second switch unit are connected in a third loop to form a third charging/discharging circuit;
the second battery, the second damping component, the second current storage component, the second energy storage component and the first switch unit are connected in a fourth loop to form a fourth charging/discharging circuit;
wherein when the second energy storage component is charged or discharges, a direction of a charging/discharging current in the third charging/discharging circuit is reverse to a direction of a charging/discharging current in the fourth charging/discharging circuit; and
wherein the switching control module is configured to control electric energy to flow among the first battery, the first energy storage component, the second energy storage component and the second battery by controlling the first switch unit and the second switch unit to switch on in alternate.

7. The heating circuit according to claim 6, wherein the first energy storage component is a first inductor, and the second energy storage component is a second inductor.

8. The heating circuit according to claim 7, wherein the switching control module is configured to control the first switch unit and the second switch unit to switch their ON/OFF states when a current in the first inductor or the second inductor reaches a preset value.

9. The heating circuit according to claim 6, wherein the first energy storage component is a first capacitor, and the second energy storage component is a second capacitor.

10. The heating circuit according to claim 1, wherein the first switch unit and/or the second switch unit comprises a switch and a one-way semiconductor component connected in parallel with the switch in a reverse direction, the switching control module is electrically connected with the switch, and the switching control module is configured to control ON/OFF of forward direction branches of the first switch unit and/or the second switch unit by controlling ON/OFF of the switch.

11. A heating circuit for a battery comprising a first battery and a second battery, the heating circuit comprising a first switch unit, a second switch unit, a first damping component, a second damping component, a first current storage component, a second current storage component, a switching control module and a first energy storage component, wherein:
the first battery, the first damping component, the first current storage component, the first energy storage component and the first switch unit are connected in a first loop to constitute a first charging/discharging circuit;
the second battery, the second damping component, the second current storage component, the first energy storage component and the second switch unit are connected in a second loop to constitute a second charging/discharging circuit;
when the first energy storage component is charged or discharges, a direction of a charging/discharging current in the second charging/discharging circuit is reverse to a direction of a charging/discharging current in the first charging/discharging circuit; and
the switching control module is electrically connected with the first switch unit and the second switch unit, and the switching control module is configured to control the first switch unit and the second switch unit to switch on in alternate, so as to control electric energy to flow among the first battery, the first energy storage component and the second battery;
the heating circuit further comprises a second energy storage component;
the first battery, the first damping component, the first current storage component, the second energy storage component and the second switch unit are connected in a third loop to form a third charging/discharging circuit;
the second battery, the second damping component, the second current storage component, the second energy storage component and the first switch unit are connected in a fourth loop to form a fourth charging/discharging circuit;
when the second energy storage component is charged or discharges, a direction of a charging/discharging current in the third charging/discharging circuit is reverse to a direction of a charging/discharging current in the fourth charging/discharging circuit;
the switching control module is configured to control electric energy to flow among the first battery, the first energy storage component, the second energy storage component and the second battery by controlling the first switch unit and the second switch unit to switch on in alternate;
the first energy storage component is a first capacitor, and the second energy storage component is a second capacitor; and
the switching control module is configured to control the first switch unit and the second switch unit to switch their ON/OFF states when a current in the first capacitor or the second capacitor reaches zero after a pair of continuous positive and negative half cycles or a pair of continuous negative and positive half cycles.

12. A heating circuit for a battery comprising a first battery and a second battery, the heating circuit comprising a first switch unit, a second switch unit, a first damping component, a second damping component, a first current storage component, a second current storage component, a switching control module and an energy storage component, wherein:
the first battery, the first damping component, the first current storage component, the energy storage component and the first switch unit are connected in a first loop to constitute a first charging/discharging circuit;
the second battery, the second damping component, the second current storage component, the energy storage component and the second switch unit are connected in a second loop to constitute a second charging/discharging circuit;
when the energy storage component is charged or discharges, a direction of a charging/discharging current in the second charging/discharging circuit is reverse to a direction of a charging/discharging current in the first charging/discharging circuit; and
the switching control module is electrically connected with the first switch unit and the second switch unit, and the switching control module is configured to control the first switch unit and the second switch unit to switch on in alternate, so as to control electric energy to flow among the first battery, the energy storage component and the second battery;
the energy storage component is a capacitor; and
the switching control module is configured to control the first switch unit and the second switch unit to switch their ON/OFF states when a current in the capacitor reaches zero after a pair of continuous positive and negative half cycles or a pair of continuous negative and positive half cycles.