An electric-electric hybrid system and a method for increasing battery temperature thereof

Abstract

The present invention discloses an electric-electric hybrid system and a method for increasing the battery temperature thereof, comprising: a first battery; a second battery connected to the first battery; and a controller connected to the first battery and the second battery respectively, wherein the controller is used to control the first battery and the second battery to charge or discharge each other so as to increase the temperature of the first battery, and can increase the temperature of the battery cell by controlling the battery to charge and discharge repeatedly, thereby achieving the effects of good heating uniformity and low heating energy consumption, and greatly improving the low-temperature driving range of the electric vehicle.

Description

Technical Field

[0001] The present invention relates to the field of electric vehicle batteries, and in particular to an electric-electric hybrid system and a method for increasing the battery temperature thereof. Background Art

[0002] With the continuous development of social economy and the continuous advancement of science and technology, electric vehicles have been well promoted and used because of their environmental protection characteristics; however, the performance of the batteries of current electric vehicles is weakened in low temperature environments. In order to ensure battery performance, the battery is often used to provide power to the PTC, and then the PTC is used to heat the water circuit, and finally the battery temperature is increased through heat transfer; however, the PTC method of heating the battery has the problems of poor heating uniformity and high heating energy consumption, which leads to a significant reduction in the low-temperature driving range of the vehicle. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes an electric-electric hybrid system that can control the repeated charging and discharging of the battery to increase the temperature of the battery core, thereby achieving good heating uniformity and low heating energy consumption, and greatly improving the low-temperature driving range of the electric vehicle.

[0004] The present invention also proposes a method for increasing the battery temperature applied to the above-mentioned electric-electric hybrid system.

[0005] An electric-electric hybrid system according to an embodiment of a first aspect of the present invention includes:

[0006] First battery;

[0007] a second battery connected to the first battery;

[0008] A controller is connected to the first battery and the second battery respectively, and is used to control the first battery and the second battery to charge or discharge each other, so as to increase the temperature of the first battery.

[0009] An electric-electric hybrid system according to an embodiment of the present invention has at least the following beneficial effects: under the control of a controller, the charge and discharge modes of a first battery and a second battery are switched, and during repeated charge and discharge of the first battery and the second battery, the internal resistance of the first battery will self-heat, causing the temperature of the battery cell to rise; and this method of causing the temperature of the battery cell to rise not only has good heating uniformity, but also has low heating energy consumption, thereby greatly extending the low-temperature driving range of the electric vehicle.

[0010] According to some embodiments of the present invention, the controller includes a first battery management system and a second battery management system, the first battery is connected to the first battery management system, the second battery is connected to the second battery management system, and the first battery management system is connected to the second battery management system.

[0011] According to some embodiments of the present invention, it also includes a current sensor and a boost circuit, the current sensor is connected to the second battery management system, the first battery, the current sensor, the boost circuit and the second battery are connected in sequence, the boost circuit is also connected to the second battery management system, and the second battery management system is used to control the boost circuit so that the first battery and the second battery are charged or discharged with each other.

[0012] According to some embodiments of the present invention, the first battery is a lithium battery, and the second battery is a supercapacitor battery.

[0013] According to some embodiments of the present invention, the boost circuit includes a first inductor, a first switching element, and a second switching element, the first switching element and the second switching element are both connected to the second battery management system, the first switching element and the second switching element are connected, one end of the first inductor is connected to the current sensor, the other end of the first inductor is connected between the first switching element and the second switching element, and the first switching element and the second switching element are both connected to the second battery.

[0014] According to some embodiments of the present invention, a first capacitor is further included, one end of the first capacitor is connected between the current sensor and the first inductor, and the other end of the first capacitor is connected to the first battery.

[0015] According to some embodiments of the present invention, a third switch element is further included, wherein the third switch element is connected to the second battery management system, and the third switch element is connected between the first switch element and the second battery.

[0016] According to some embodiments of the present invention, a first relay group is further included, wherein the first relay group is connected between the first battery and the current sensor, and the first relay group is connected to the first battery management system.

[0017] According to some embodiments of the present invention, a second relay group and an external output circuit are further included, the second battery, the second relay group and the external output circuit are connected in sequence, and the second relay group is connected to the second battery management system.

[0018] The battery temperature increasing method according to the second embodiment of the present invention is applied to the electric-electric hybrid system mentioned in the first embodiment.

[0019] The battery temperature raising method according to the embodiment of the present invention has at least the following beneficial effects: under the control of the controller, the charge and discharge modes between the first battery and the second battery are switched, and during the repeated charge and discharge of the first battery and the second battery, the internal resistance of the first battery will self-heat, causing the temperature of the battery cell to rise; and this method of raising the temperature of the battery cell not only has good heating uniformity, but also has low heating energy consumption, which greatly extends the low-temperature driving range of the electric vehicle.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0022] Figure 1 is a principle block diagram of an electric-electric hybrid system according to an embodiment of the present invention;

[0023] Figure 2 A circuit schematic diagram of an electric-electric hybrid system according to an embodiment of the present invention;

[0024] Figure 3 A schematic diagram of the discharge of a first battery of an electric-electric hybrid system under a battery heating condition according to an embodiment of the present invention;

[0025] Figure 4 A schematic diagram of charging a first battery of an electric-electric hybrid system under battery heating conditions according to an embodiment of the present invention;

[0026] Figure 5 A schematic diagram of charging of an electric-electric hybrid system under dual battery power output conditions according to an embodiment of the present invention;

[0027] Figure 6 A discharge schematic diagram of an electric-electric hybrid system in a dual-battery power output state according to an embodiment of the present invention;

[0028] Figure 7 FIG. 4 is a flow chart of the steps of a method for increasing battery temperature according to another embodiment of the present invention.

[0029] Reference numerals:

[0030] The controller 10 , the first battery 100 , the first battery management system 200 , the second battery 300 , the second battery management system 400 , the first relay group 500 , the second relay group 600 , and the external output circuit 700 . DETAILED DESCRIPTION

[0031] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0032] In the description of the present invention, it should be understood that descriptions involving orientation, such as orientation or positional relationship indicated as up, down, etc., are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0033] In the description of the present invention, unless otherwise clearly defined, words such as setting and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0034] Reference Figure 1 , an electric-electric hybrid system according to an embodiment of the present invention comprises: a first battery 100; a second battery 300 connected to the first battery 100; a controller 10 connected to the first battery 100 and the second battery 300 respectively, and the controller 10 is used to control the first battery 100 and the second battery 300 to charge or discharge each other, so as to increase the temperature of the first battery 100. Under the control of the controller 10, the charge and discharge modes of the first battery 100 and the second battery 300 are switched, and during the repeated charge and discharge of the first battery 100 and the second battery 300, the internal resistance of the first battery 100 will self-heat, so that the temperature of the battery cell rises; and this method of increasing the temperature of the battery cell not only has good heating uniformity, but also has low heating energy consumption, which well extends the low-temperature driving range of the electric vehicle.

[0035] In some specific embodiments of the present invention, the controller 10 includes a first battery management system 200 and a second battery management system 400, the first battery 100 is connected to the first battery management system 200, the second battery 300 is connected to the second battery management system 400, and the first battery management system 200 is connected to the second battery management system 400. The controller 10 includes the first battery management system 200 and the second battery management system 400, the first battery management system 200 can collect relevant information of the first battery 100, the second battery management system 400 can collect relevant information of the second battery 300, and then the first battery management system 200 and the second battery management system 400 mutually transmit information, and the transmitted information includes battery voltage, temperature, SOC, SOP and current information, and the second battery management system 400 can judge the charge and discharge mode of the first battery 100 and the second battery 300 based on the relevant information transmitted by the first battery management system 200, and then control the first battery 100 to switch the charge and discharge mode, so that the internal resistance of the first battery 100 is heated during repeated charge and discharge, and the temperature of the battery cell rises.

[0036] Reference Figure 2 In some specific embodiments of the present invention, a current sensor CS and a boost circuit are further included. The current sensor CS is connected to the second battery management system 400. The first battery 100, the current sensor CS, the boost circuit and the second battery 300 are connected in sequence. The boost circuit is also connected to the second battery management system 400. The second battery management system 400 is used to control the boost circuit so that the first battery 100 and the second battery 300 can charge or discharge each other. The current sensor CS is arranged between the first battery 100 and the second battery 300, so that the current sensor CS can feed back the detected line current to the second battery management system 400. Then, the second battery management system 400 controls the boost circuit to boost the voltage according to the received current, thereby realizing the switching of the charging and discharging modes of the first battery 100 and the second battery 300. In the process of repeated charging and discharging of the first battery 100 and the second battery 300, the internal resistance of the battery will self-heat, so that the temperature of the battery cell rises, so that the heating uniformity is good, and the heating energy consumption is low, which well extends the low-temperature driving range of the electric vehicle.

[0037] In some specific embodiments of the present invention, the first battery 100 is a lithium battery, and the second battery 300 is a supercapacitor battery. Lithium batteries are large-capacity batteries with low output power, and are energy-type batteries; while supercapacitor batteries are small-capacity batteries, but with high output power, and are power-type batteries, and the voltage platform of supercapacitor batteries is higher than that of lithium batteries; so when the first battery 100 charges the second battery 300, it is necessary to perform a boost process through a boost circuit; but when the second battery 300 charges the first battery 100, no additional boost device is required. Among them, the lithium battery can be a ternary lithium battery or a lithium iron phosphate battery.

[0038] Reference Figure 2 In some specific embodiments of the present invention, the boost circuit includes a first inductor L1, a first switch element G1 and a second switch element G2. The first switch element G1 and the second switch element G2 are both connected to the second battery management system 400. The first switch element G1 and the second switch element G2 are connected. One end of the first inductor L1 is connected to the current sensor CS, and the other end of the first inductor L1 is connected between the first switch element G1 and the second switch element G2. The first switch element G1 and the second switch element G2 are both connected to the second battery 300. The first switch element G1 and the second switch element G2 are both controlled by the second battery management system 400. The first inductor L1 is used to generate self-induced electromotive force to achieve boosting effect. The second battery management system 400 controls the first switch element G1 and the second switch element G2 to boost voltage and realize the switching of charging and discharging modes.

[0039] Reference Figure 2 In some specific embodiments of the present invention, a first capacitor C1 is further included, one end of the first capacitor C1 is connected between the current sensor CS and the first inductor L1, and the other end of the first capacitor C1 is connected to the first battery 100. The first capacitor C1 is an energy storage capacitor, which plays a role in smoothing the voltage.

[0040] Reference Figure 2 In some specific embodiments of the present invention, a third switch element G3 is further included, and the third switch element G3 is connected to the second battery management system 400. The third switch element G3 is connected between the first switch element G1 and the second battery 300. The third switch element G3 is connected to the second battery management system 400, so that the second battery management system 400 can control the third switch element G3 to determine whether the second battery 300 participates in the charging and discharging of the high-voltage circuit.

[0041] Reference Figure 2In some specific embodiments of the present invention, a first relay group 500 is further included. The first relay group 500 is connected between the first battery 100 and the current sensor CS, and the first relay group 500 is connected to the first battery management system 200. The first relay group 500 is connected to the first battery management system 200, so that the first relay group 500 is controlled by the first battery management system 200, and the current transfer between the first battery 100 and the second battery 300 can be achieved by controlling the first relay group 500.

[0042] Reference Figure 2 In some specific embodiments of the present invention, the first relay group 500 includes a first relay K1, a second relay K2 and a first resistor R1, the first battery 100, the first resistor R1, the first relay K1 and the current sensor CS are connected in sequence, the first battery 100, the second relay K2 and the current sensor CS are connected in sequence, and the first relay K1 and the second relay K2 are both connected to the first battery management system 200. The first relay K1 and the second relay K2 are both controlled by the first battery management system 200. When the first relay K1 is closed and the second relay K2 is opened, the first battery 100 can charge the first capacitor C1 to achieve loop pre-charging.

[0043] Reference Figure 2 In some specific embodiments of the present invention, a second relay group 600 and an external output circuit 700 are further included. The second battery 300, the second relay group 600 and the external output circuit 700 are connected in sequence, and the second relay group 600 is connected to the second battery management system 400. Since the vehicle has high requirements for battery performance when charging and discharging at high power, and lithium batteries are difficult to meet the requirements well due to the limitations of their own characteristics, supercapacitor batteries are used in conjunction with supercapacitor batteries, which have high-power charging and discharging characteristics and can well reduce the requirements for lithium battery performance; the second battery management system 400 can control the output power of the external output circuit 700 by controlling the second relay group 600, and when the first battery 100 and the third battery 300 are discharged together, the output power requirements of the vehicle are well met.

[0044] In some specific embodiments of the present invention, the second relay group 600 includes a second resistor R2, a third relay K3, a fourth relay K4 and a fifth relay K5, the second battery 300, the second resistor R2, the third relay K3 and the external output circuit 700 are connected in sequence, the second battery 300, the fourth relay K4 and the external output circuit 700 are connected in sequence, and the second battery 300, the fifth relay K5 and the external output circuit 700 are connected in sequence. The third relay K3, the fourth relay K4 and the fifth relay K5 are all connected to the second battery management system 400, so that the third relay K3, the fourth relay K4 and the fifth relay K5 are all controlled by the second battery management system 400, and then the second battery management system 400 can control and process the output power of the electric vehicle.

[0045] In some specific embodiments of the present invention, the first switch element G1, the second switch element G2 and the third switch element G3 are IGBTs or MOS tubes. IGBTs or MOS tubes are commonly used triodes with stable performance and can be well used as switch elements in the embodiments of the present invention.

[0046] The following provides a specific embodiment to illustrate how the electric-electric hybrid system can achieve battery heating by charging and discharging each other in a low temperature environment; and how the electric-electric hybrid system can operate under power demand conditions to achieve

[0047]

[0048] High power output requirements.

[0049] Reference Figure 3 and Figure 4 , the scenario of "under low temperature environment (below -15℃), the driver ends the current driving (or the driver can remotely notify the vehicle through the mobile phone before starting the driving)" is used for explanation. Steps 1, 2 and 3 are used to realize mutual charging and discharging of the first battery 100 and the second battery 300. According to the relevant steps in Table 1, the first battery 100 is controlled to charge and discharge, wherein, Figure 3 In the case of inputting PWM_1 signal, when the current Ics1 is positive, it means that the first battery 100 is discharging. Similarly, Figure 4 In the case of inputting the PWM_2 signal, when the current of Ics1 is negative, it means that the first battery 100 is being charged. And in the process of charging and discharging the first battery 100, firstly, when the heating condition is met, step 1 is executed, then step 2 is executed, and then step 3 is executed, and it is determined whether the temperature of the battery cell is greater than the preset threshold value. If not, step 2 and step 3 are executed again until the temperature of the battery cell is greater than the preset threshold value, and then the heating process is stopped.

[0050] Table 1

[0051] Reference Figure 5 and Figure 6 , the scenario of "when the driver accelerates / decelerates suddenly" is used for explanation. Based on the driver's command torque (calculated by MCU and sent via CAN), the second battery management system 400 determines whether auxiliary charging and discharging is required. According to the relevant steps in Table 2, the second battery 300 will also be discharged to improve the discharge capacity of the electric vehicle and meet the requirements of high power output.

[0052]

[0053] Table 2

[0054] exist Figure 5 When Ics1 is negative, it means that the first battery 100 is being charged. BAT2 When it is negative, it means that the second battery 300 is also being charged; Figure 6 When Ics1 is positive, it means that the first battery 100 is discharging. BAT2 When it is positive, it means that the second battery 300 is also undergoing a discharge process.

[0055] This system can be used in low-temperature environments. When the driver turns off the engine and leaves the vehicle, when the temperature of the lithium battery drops to a certain value, the lithium battery and the supercapacitor battery discharge each other to maintain the temperature of the lithium battery. When the user uses the car again, he can use it without waiting for heating. If external heating is required in a low-temperature environment, the PTC can even be cancelled and heating can be performed through MOT stall control; the cooling demand in a high-temperature environment is also reduced (because the battery does not need to discharge too much current). Generally, electric vehicles use lithium batteries with high energy density. The output / input power of lithium batteries is limited in low-temperature and high-temperature environments, low SOC, and high SOC, and it is difficult to meet high-power charging and discharging scenarios such as rapid acceleration / rapid deceleration; in order to achieve high-power output / input, supercapacitor batteries are connected in parallel to the high-voltage circuit, which reduces the performance requirements for lithium batteries.

[0056] It can be seen from the above scheme that under the control of the controller 10, the charge and discharge modes of the first battery 100 and the second battery 300 are switched. During the repeated charge and discharge of the first battery 100 and the second battery 300, the internal resistance of the first battery 100 will self-heat, causing the temperature of the battery cell to rise; and this method of increasing the temperature of the battery cell not only has good heating uniformity, but also has low heating energy consumption, which greatly extends the low-temperature driving range of the electric vehicle.

[0057] Reference Figure 7Another embodiment of the present invention provides a battery temperature raising method, which can be applied to the electric-electric hybrid system provided in the above embodiment; wherein the battery temperature raising method includes the following steps:

[0058] S100, judging whether the heating conditions are met.

[0059] In this embodiment, this step first determines whether the conditions for heating the battery are met, and only when the conditions are met will the battery cell be heated. The heating conditions may include the current ambient temperature and the current battery performance.

[0060] S200, when the heating condition is met, the controller controls the first battery and the second battery to charge and discharge each other, so that the temperature of the battery cell of the first battery is heated and increased.

[0061] In this embodiment, when the heating condition is met in this step, the controller controls the first battery and the second battery to charge or discharge each other. During the repeated charging and discharging process, the internal resistance of the first battery self-heats, thereby increasing the temperature of the battery cell.

[0062] S300, determining whether the temperature of the battery cell of the first battery reaches a stop threshold, if so, stopping the mutual charging and discharging; otherwise, continuing the mutual charging and discharging.

[0063] In this embodiment, this step determines whether the battery cell temperature of the first battery reaches the stop threshold. When the stop threshold is reached, the heating process of the first battery is stopped; when the stop threshold has not been reached, the controller continues to control the first battery to perform repeated charge and discharge processes and continues the heating process until the battery cell temperature of the first battery reaches the stop threshold.

[0064] It can be seen from the above scheme that under the control of the controller 10, the charge and discharge modes of the first battery 100 and the second battery 300 are switched. During the repeated charge and discharge of the first battery 100 and the second battery 300, the internal resistance of the first battery 100 will self-heat, causing the temperature of the battery cell to rise; and this method of increasing the temperature of the battery cell not only has good heating uniformity, but also has low heating energy consumption, which greatly extends the low-temperature driving range of the electric vehicle.

[0065] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0066] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An electric-electric hybrid system, characterized in that: include: First battery; a second battery connected to the first battery; a controller, connected to the first battery and the second battery respectively, and configured to control the first battery and the second battery to charge or discharge each other, so as to increase the temperature of the first battery; Wherein, the controller includes a first battery management system and a second battery management system, the first battery is connected to the first battery management system, the second battery is connected to the second battery management system, and the first battery management system is connected to the second battery management system; It also includes a current sensor and a boost circuit, wherein the current sensor is connected to the second battery management system, the first battery, the current sensor, the boost circuit and the second battery are connected in sequence, the boost circuit is also connected to the second battery management system, and the second battery management system is used to control the boost circuit so that the first battery and the second battery are charged or discharged mutually; The boost loop includes a first inductor, a first switch element, and a second switch element, wherein the first switch element and the second switch element are both connected to the second battery management system, the first switch element and the second switch element are connected, one end of the first inductor is connected to the current sensor, the other end of the first inductor is connected between the first switch element and the second switch element, and the first switch element and the second switch element are both connected to the second battery; It also includes a second relay group and an external output circuit, the second battery, the second relay group and the external output circuit are connected in sequence, and the second relay group is connected to the second battery management system; Also includes a third switch element, the third switch element is connected to the second battery management system, and the third switch element is connected between the first switch element and the second battery; It also includes a first relay group, the first relay group is connected between the first battery and the current sensor, and the first relay group is connected to the first battery management system; The second relay group includes a second resistor, a third relay, a fourth relay and a fifth relay, the second battery, the second resistor, the third relay and the external output circuit are connected in sequence, the second battery, the fourth relay and the external output circuit are connected in sequence, and the second battery, The fifth relay and the external output circuit are connected in sequence; Wherein, in the case of sudden deceleration of the vehicle, the third relay is controlled to be in an open state, the fourth relay and the fifth relay are in a closed state, the first relay is in an open state, the second relay is in a closed state, the third switch element is in a closed state, and the first switch element and the second switch element are operated according to the PWM_3 signal; In the case of sudden acceleration of the vehicle, the third relay is controlled to be in an open state, the fourth relay and the fifth relay are in a closed state, the first relay is in an open state, the second relay is in a closed state, the third switch element is in a closed state, and the first switch element and the second switch element are operated according to the PWM_4 signal.

2. The electric-electric hybrid system according to claim 1, characterized in that: The first battery is a lithium battery, and the second battery is a supercapacitor battery.

3. The electric-electric hybrid system according to claim 1, characterized in that: It also includes a first capacitor, one end of which is connected between the current sensor and the first inductor, and the other end of which is connected to the first battery.

4. A method for increasing the battery temperature of an electric-electric hybrid system according to any one of claims 1 to 3 The method is characterized in that include: Determine whether the heating conditions are met; When the heating condition is met, the controller controls the first battery and the second battery to charge and discharge each other, so that the temperature of the battery cell of the first battery is heated up; It is determined whether the temperature of the battery cell of the first battery reaches a stop threshold, and if so, the mutual charging and discharging is stopped; otherwise, the mutual charging and discharging is continued.

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