A power battery low-temperature intelligent pulse heating circuit, a power battery and a car

Abstract

A low-temperature intelligent pulse heating circuit for power batteries, a power battery, and an automobile are disclosed, relating to the field of new energy vehicles. The circuit includes: a first relay, an inductor, a first switching transistor, and a second switching transistor. The first and second switching transistors have parasitic diodes with reverse conduction, or the switching transistors include a switch body and a diode connected in reverse parallel with the switch body. One end of the inductor is connected to the common terminal of the first and second battery packs, and the other end of the inductor is connected to the common terminal of the first and second switching transistors. The other ends of the first and second switching transistors are respectively connected to the other ends of the first and second battery packs. The branch formed by the first and second switching transistors is connected in parallel with the vehicle's bus capacitor. This circuit provides a reliable hardware foundation for achieving rapid and uniform heating of the battery pack.

Description

Technical Field

[0001] This utility model relates to the field of new energy vehicle technology, specifically to a low-temperature intelligent pulse heating circuit for a power battery, a power battery, and a vehicle. Background Technology

[0002] Against the backdrop of the rapid development of the new energy vehicle industry, the safety and efficiency of power batteries under all temperature conditions have become key technological challenges. Research shows that solid-state batteries exhibit significant performance degradation in low-temperature environments: their discharge capacity decreases significantly with decreasing temperature, and lithium dendrite precipitation at the anode is prone to occur during low-temperature charging. These technological bottlenecks not only limit the energy output efficiency of battery systems but also pose a severe challenge to the operational reliability of electric vehicles in extreme environments.

[0003] Traditional battery thermal management technology mainly relies on external heating methods, that is, indirectly heating the battery pack by circulating heat through the battery pack's thermal management coolant circuit, thereby increasing the cell temperature. This method has obvious technical limitations: 1) long heat conduction paths lead to low heating rates; 2) uneven temperature gradient distribution causes the risk of local overheating; 3) system response lag affects temperature control accuracy. Utility Model Content

[0004] In view of this, the present invention provides a low-temperature intelligent pulse heating circuit for a power battery, a power battery, and a car, so as to achieve rapid and uniform heating of the power battery.

[0005] To achieve the above objectives, the present invention provides the following technical solutions:

[0006] A low-temperature intelligent pulse heating circuit for power batteries, comprising:

[0007] A first relay, an inductor, a first switching transistor, and a second switching transistor, wherein the first and second switching transistors have a parasitic diode that conducts in reverse, or the first and second switching transistors include a switch body and a diode connected in reverse parallel with the switch body.

[0008] The first terminal of the first relay is connected to the first node, and the first node is connected to the cathode of the first battery pack and the anode of the second battery pack.

[0009] The first end of the inductor is connected to the second end of the first relay;

[0010] The first terminal of the first switching transistor is connected to the positive terminal of the first battery pack and the first terminal of the vehicle bus capacitor, and the second terminal of the first switching transistor is connected to the second terminal of the inductor.

[0011] The first end of the second switching transistor is connected to the second end of the inductor, and the second end of the second switching transistor is connected to the negative terminal of the second battery pack and the second end of the vehicle bus capacitor.

[0012] Optionally, the aforementioned low-temperature intelligent pulse heating circuit for power batteries also includes:

[0013] A pre-charging circuit is disposed between the cathode of the first battery pack and the first switching transistor;

[0014] The pre-charging circuit includes a pre-charging relay, a pre-charging resistor, and a main positive relay;

[0015] The first terminal of the precharge relay is connected to the cathode of the first battery pack;

[0016] The first terminal of the pre-charge resistor is connected to the second terminal of the pre-charge relay, and the second terminal of the pre-charge resistor is connected to the first terminal of the first switching transistor.

[0017] The first terminal of the main positive relay is connected to the cathode of the first battery pack, and the second terminal of the main positive relay is connected to the first terminal of the first switching transistor.

[0018] Optionally, the aforementioned low-temperature intelligent pulse heating circuit for power batteries also includes:

[0019] A fuse protector is disposed between the first node and the first terminal of the first relay.

[0020] Optionally, the aforementioned low-temperature intelligent pulse heating circuit for power batteries also includes:

[0021] A switch controller, comprising an MCU controller, a first switch drive circuit, and a second switch drive circuit;

[0022] The output terminal of the MCU controller is connected to the control terminal of the first switch driving circuit and the second switch driving circuit. The output terminal of the first switch driving circuit is connected to the control terminal of the first switch transistor, and the output terminal of the second switch driving circuit is connected to the control terminal of the second switch transistor.

[0023] Optionally, in the above-mentioned low-temperature intelligent pulse heating circuit for power batteries, at least one of the first and second switching transistors is a MOSFET or a diode.

[0024] Optionally, in the above-mentioned low-temperature intelligent pulse heating circuit for power batteries, the first battery pack and the second battery pack are battery packs with the same number of cells.

[0025] Optionally, in the above-mentioned low-temperature intelligent pulse heating circuit for power batteries, the inductor is an adjustable inductor.

[0026] A power battery, comprising any one of the power battery low-temperature intelligent pulse heating circuits described above.

[0027] An automobile includes a power battery and the aforementioned power battery low-temperature intelligent pulse heating circuit.

[0028] Based on the above technical solution, the solution provided by this utility model embodiment, when heating the battery pack, can repeatedly control the first switch to be turned on, the second switch to be turned off, the first switch to be turned off, and the second switch to be turned on based on a preset duty cycle, so as to heat the first battery pack and the second battery pack by high-frequency discharge through the inductor. During the heating process, the heat is released by the internal resistance of the battery pack, and the heat release is uniform and fast. Therefore, this solution provides a reliable hardware foundation for realizing rapid and uniform heating of the battery pack. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of the low-temperature intelligent pulse heating circuit for power batteries disclosed in the embodiments of this application;

[0031] Figure 2 A schematic diagram of the current path in the circuit when the high-voltage bus capacitor is precharged to the battery voltage;

[0032] Figure 3 This is a schematic diagram of the current path of the low-temperature intelligent pulse heating circuit for the power battery during Phase 1.

[0033] Figure 4 This is a schematic diagram of the current path of the low-temperature intelligent pulse heating circuit for the power battery during stage 2.

[0034] Figure 5 This is a schematic diagram of the current path of the low-temperature intelligent pulse heating circuit for the power battery during stage 3.

[0035] Figure 6 This is a schematic diagram of the current path of the low-temperature intelligent pulse heating circuit for the power battery during stage 4. Detailed Implementation

[0036] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0037] The applicant's research revealed that, compared to heating methods based on the battery pack's thermal management coolant circuit, self-heating technology based on the battery's internal resistance characteristics exhibits significant advantages: Under low-temperature conditions, by controlling the battery to perform alternating current charging and discharging at a specific frequency, the inherent internal resistance characteristics of the electrode materials generate a Joule heating effect to heat the battery pack. This internal heating method has the following characteristics: 1) The heat source is directly generated inside the cell, resulting in the shortest heat transfer path; 2) Temperature field distribution uniformity is improved by more than 85%; 3) It can achieve a rapid temperature rise of 3-5°C per minute, allowing the battery to recover to its optimal operating temperature range within 120 seconds.

[0038] Based on the self-heating technology of battery internal resistance characteristics, this application provides a low-temperature intelligent pulse heating circuit for power batteries. (See [link to relevant documentation]). Figure 1 The circuit may include:

[0039] A first relay K1, an inductor L1, a first switch Q1 and a second switch Q2, wherein the first switch Q1 and the second switch Q2 have parasitic diodes that conduct in reverse or the switch includes a switch body and a diode connected in reverse parallel with the switch body.

[0040] The first terminal of the first relay K1 is connected to the first node, and the first node is connected to the cathode of the first battery pack Bat1 and the anode of the second battery pack Bat2.

[0041] The first terminal of the inductor L1 is connected to the second terminal of the first relay K1;

[0042] The first terminal of the first switch Q1 is connected to the positive terminal of the first battery pack Bat1 and the first terminal of the vehicle bus capacitor C, and the second terminal of the first switch Q1 is connected to the second terminal of the inductor L1.

[0043] The first terminal of the second switch Q2 is connected to the second terminal of the inductor L1, and the second terminal of the second switch Q2 is connected to the negative terminal of the second battery pack Bat2 and the second terminal of the vehicle bus capacitor C.

[0044] The above-described solution disclosed in this embodiment can achieve self-heating of the battery pack by controlling the conduction state of the first switch Q1 and the second switch Q2 in the low-temperature intelligent pulse heating circuit of the power battery. This circuit provides hardware support for achieving self-heating of the battery pack.

[0045] Specifically, when the power battery (including the first battery pack Bat1 and the second battery pack Bat2) requires heating, the high-voltage bus capacitor is pre-charged to the battery voltage, and then the first relay K1 is closed. This action prevents issues such as the first relay K1 closing during the charging process of the high-voltage bus capacitor. Figure 2 The current loop shown causes the first relay K1 to carry a large current for a long time, resulting in the first relay K1 sticking together.

[0046] When the first relay K1 is closed, the circuit can enter a stable working state. During this process, the first switch Q1 and the second switch Q2 need to be controlled to turn on and off with a duty cycle of 50% respectively, so as to pulse power the first battery pack Bat1 and the second battery pack Bat2, so that the internal resistance of the first battery pack Bat1 and the second battery pack Bat2 dissipates heat, thereby heating the first battery pack Bat1 and the second battery pack Bat2 evenly and quickly.

[0047] Specifically, after the circuit enters a stable working state, the first switch Q1 and the second switch Q2 are controlled to turn on and off with a duty cycle of 50% respectively, so as to realize the repeated charging and discharging function of the first battery pack Bat1 and the second battery pack Bat2. In this circuit, since the vehicle bus capacitor C is equivalent to an energy pool, it will also participate in the entire working process. This work is mainly divided into four stages: stage 1 to stage 4.

[0048] Phase 1: See Figure 3 The first switch Q1 is turned off, and the second switch Q2 is turned on. At this time, the second battery pack Bat2 discharges. The discharge current of the second battery pack Bat2 and the current of the inductor L1 gradually increase according to the slope Vbat2 / L1. The bus capacitor is in the discharge state and charges the first battery pack Bat1. Vbat2 is the output voltage of the second battery pack Bat2, and L1 is the inductance value of the inductor L1.

[0049] Phase 2: See Figure 4 When the second switch Q2 is turned off, the first switch Q1 is turned on. Since the current in inductor L1 cannot change abruptly, it needs to freewheel through the first switch Q1. At this time, inductor L1 is charging the first battery pack Bat1 at high frequency, and the charging current gradually decreases with a slope of Vbat1 / L1 until it becomes 0. The bus capacitor is in a charging state.

[0050] Phase 3: See Figure 5 When the second switch Q2 is turned off and the first switch Q1 is turned on, the current in the inductor L1 reverses direction, and the first battery pack Bat1 discharges, with the discharge current gradually increasing at a slope of Vbat1 / L1. The bus capacitor is in a discharging state.

[0051] Phase 4: See Figure 6 When the second switch Q2 is turned on and the first switch Q1 is turned off, the current of the inductor L1 cannot change abruptly and is freewheeled through the second switch Q2. At this time, the second battery pack Bat2 is charged, and the charging current gradually decreases with the slope of Vbat2 / L1 until it is 0. The bus capacitor is in the charging state, and Vbat2 is the output voltage of the second battery pack Bat2.

[0052] During the battery pack heating process, the power battery low-temperature intelligent pulse heating circuit sequentially executes stage 1, stage 2, stage 3 and stage 4, causing the first battery pack Bat1 and the second battery pack Bat2 to repeatedly charge and discharge at high frequency. After detecting that the battery temperature in the first battery pack Bat1 and the second battery pack Bat2 has reached the set temperature, the above state is exited. When exiting, the first relay K1 is first controlled to disconnect, and then the high voltage of the whole vehicle is controlled.

[0053] In this embodiment, a pre-charging circuit may also be provided in the above circuit, and the pre-charging circuit is provided between the cathode of the first battery pack Bat1 and the first switching transistor Q1.

[0054] The pre-charging circuit includes a pre-charging relay K2, a pre-charging resistor R, and a main positive relay K3;

[0055] The first terminal of the precharge relay K2 is connected to the cathode of the first battery pack Bat1;

[0056] The first end of the pre-charge resistor R is connected to the second end of the pre-charge relay K2, and the second end of the pre-charge resistor R is connected to the first end of the first switch Q1.

[0057] The first terminal of the main positive relay K3 is connected to the cathode of the first battery pack Bat1, and the second terminal of the main positive relay K3 is connected to the first terminal of the first switching transistor Q1.

[0058] When the high-voltage bus capacitor is pre-charged to the battery voltage, the first relay K1 is opened and the pre-charge relay K2 is closed. At this time, the output current of the first battery pack Bat1 and the second battery pack Bat2 flows through the pre-charge resistor R to charge the vehicle bus capacitor C. After the vehicle bus capacitor C is fully charged, the pre-charge relay K2 is opened and the main positive relay K3 is closed. Corresponding to the main positive relay K3, the circuit may also include a main negative relay K4, which is located between the negative terminal of the second battery pack Bat2 and the second switching transistor Q2.

[0059] In this embodiment, in order to prevent the components in the circuit from being damaged by high current, the circuit also includes a fuse protector F1. The fuse protector F1 is disposed between the first node and the first terminal of the first relay K1. When the current in the circuit is too high, the fuse protector F1 performs fuse protection.

[0060] In this embodiment, the circuit may further include a switch controller for controlling the conduction state of the first switch Q1 and the second switch Q2. The switch controller includes an MCU controller, a first switch driver circuit IC1, and a second switch driver circuit IC2. The first switch driver circuit IC1 drives the first switch Q1 to control its conduction state, and the second switch driver circuit IC2 drives the second switch Q2 to control its conduction state. The output terminal of the MCU controller is connected to the control terminals of the first switch driver circuit IC1 and the second switch driver circuit IC2. The output terminal of the first switch driver circuit is connected to the control terminal of the first switch Q1, and the output terminal of the second switch driver circuit is connected to the control terminal of the second switch Q2. During the battery pack heating process, the MCU is used to send a configured PWM control signal to the first switch drive circuit and the second switch drive circuit, so that the first switch Q1 and the second switch Q2 are sequentially turned on and off according to the phase 1, phase 2, phase 3 and phase 4. The duty cycle in the PWM control signal can be 50%, so that the inductor L1 sends a high-frequency current signal to the battery pack to be heated.

[0061] In this embodiment, the types of the first switch Q1 and the second switch Q2 can be selected according to the relevant requirements. For example, at least one of the first switch Q1 and the second switch Q2 is a MOSFET or a diode.

[0062] In this embodiment, the first battery pack Bat1 and the second battery pack Bat2 are battery packs with the same number of cells. At this time, during the heating process of the first battery pack Bat1 and the second battery pack Bat2, the discharge current of the first battery pack Bat1 and the second battery pack Bat2 is the same. At this time, the heat released by the first battery pack Bat1 and the second battery pack Bat2 is the same, thereby achieving uniform heating of the battery pack and preventing the problem of the first battery pack Bat1 having a high temperature and the second battery pack Bat2 having a low temperature, or the first battery pack Bat1 having a low temperature and the second battery pack Bat2 having a high temperature.

[0063] In the technical solution disclosed in this embodiment, the inductor L1 is an adjustable inductor L1. The user can select the inductance value of the inductor L1 to be connected in the circuit according to the design requirements. By adjusting the inductance value of L1, the total discharge time of the inductor L1 during discharge can be adjusted to achieve gentle heating of the battery pack.

[0064] This embodiment discloses a power battery, including any of the power battery low-temperature intelligent pulse heating circuits described above.

[0065] An automobile includes a power battery and a low-temperature intelligent pulse heating circuit for the power battery as described in any of the first claims above.

[0066] For ease of description, the above system is described by dividing it into various modules based on their functions. Of course, in implementing this utility model, the functions of each module can be implemented in one or more software and / or hardware components.

[0067] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. Components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0068] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0069] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A low-temperature intelligent pulse heating circuit for power batteries, characterized in that, include: A first relay, an inductor, a first switching transistor, and a second switching transistor, wherein the first and second switching transistors have a parasitic diode that conducts in reverse, or the first and second switching transistors include a switch body and a diode connected in reverse parallel with the switch body. The first terminal of the first relay is connected to the first node, and the first node is connected to the cathode of the first battery pack and the anode of the second battery pack. The first end of the inductor is connected to the second end of the first relay; The first terminal of the first switching transistor is connected to the positive terminal of the first battery pack and the first terminal of the vehicle bus capacitor, and the second terminal of the first switching transistor is connected to the second terminal of the inductor. The first end of the second switching transistor is connected to the second end of the inductor, and the second end of the second switching transistor is connected to the negative terminal of the second battery pack and the second end of the vehicle bus capacitor.

2. The low-temperature intelligent pulse heating circuit for power batteries according to claim 1, characterized in that, Also includes: A pre-charging circuit is disposed between the cathode of the first battery pack and the first switching transistor; The pre-charging circuit includes a pre-charging relay, a pre-charging resistor, and a main positive relay; The first terminal of the precharge relay is connected to the cathode of the first battery pack; The first terminal of the pre-charge resistor is connected to the second terminal of the pre-charge relay, and the second terminal of the pre-charge resistor is connected to the first terminal of the first switching transistor. The first terminal of the main positive relay is connected to the cathode of the first battery pack, and the second terminal of the main positive relay is connected to the first terminal of the first switching transistor.

3. The low-temperature intelligent pulse heating circuit for power batteries according to claim 1, characterized in that, Also includes: A fuse protector is disposed between the first node and the first terminal of the first relay.

4. The low-temperature intelligent pulse heating circuit for power batteries according to claim 1, characterized in that, Also includes: A switch controller, comprising an MCU controller, a first switch drive circuit, and a second switch drive circuit; The output terminal of the MCU controller is connected to the control terminal of the first switch driving circuit and the second switch driving circuit. The output terminal of the first switch driving circuit is connected to the control terminal of the first switch transistor, and the output terminal of the second switch driving circuit is connected to the control terminal of the second switch transistor.

5. The low-temperature intelligent pulse heating circuit for power batteries according to claim 1, characterized in that, At least one of the first and second switching transistors is a MOSFET or a diode.

6. The low-temperature intelligent pulse heating circuit for power batteries according to claim 1, characterized in that, The first battery pack and the second battery pack are battery packs with the same number of battery cells.

7. The low-temperature intelligent pulse heating circuit for power batteries according to claim 1, characterized in that, The inductor is an adjustable inductor.

8. A power battery, characterized in that, Includes the low-temperature intelligent pulse heating circuit for power batteries as described in any one of claims 1-7.

9. A car, characterized in that, It includes a power battery and the low-temperature intelligent pulse heating circuit for the power battery as described in any one of claims 1-7.

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