A battery self-heating circuit and vehicle

Abstract

The embodiment of the application provides a battery self-heating circuit and a vehicle, wherein the battery self-heating circuit comprises: a battery pack; and a resonance device; the battery pack comprises: a first battery module and a second battery module; the resonance device comprises: a power switch, and the resonance device is used for generating high-frequency current to heat the battery pack based on the opening and closing of the power switch; the first battery module comprises: a first upper battery submodule and a first lower battery submodule; the second battery module comprises: a second upper battery submodule and a second lower battery submodule; the second end of the first upper battery submodule is connected with the second end of the second lower battery submodule; the first end of the resonance device is connected with the second end of the first upper battery submodule; the second end of the resonance device is connected with the second end of the second upper battery submodule; and the battery capacity of the first battery module and the second battery module is equal. Compared with the battery self-heating circuit with the same capacity in the prior art, the circuit can reduce the voltage borne by the power switch in the resonance device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy battery, in particular to a battery self-heating circuit and a vehicle. BACKGROUND

[0002] The performance of the power battery of a new energy vehicle is poor at low temperature, and therefore, the battery of the vehicle needs to be heated when the vehicle is running or parked for charging.

[0003] The existing battery pack is formed by connecting a plurality of batteries in series, and the battery AC internal resistance heating circuit can be composed of the battery pack and a resonance circuit. When the battery needs to be heated, the heating circuit is operated at a certain switching frequency, so that an alternating current of a certain frequency passes through the battery, thereby achieving the heating of the battery. However, the circuit of the prior art involves a method that makes the power switch of the battery self-heating circuit bear at least twice the voltage of the battery when the circuit is working, which requires a higher voltage resistance of the power switch, increases the manufacturing cost of the circuit and the risk of breakdown of the power switch. SUMMARY

[0004] The purpose of the embodiments of the present application is to provide a battery self-heating circuit that can reduce the voltage resistance requirement of the power switch in the resonance circuit when the battery self-heating circuit is working.

[0005] In a first aspect, the embodiments of the present application provide a battery sub-heating circuit, comprising: a battery pack; a resonance device;

[0006] The battery pack comprises: a first battery module, a second battery module;

[0007] The resonance device comprises: a power switch, and the resonance device is configured to generate a frequency current based on the opening and closing of the power switch to heat the battery pack.

[0008] The first battery module comprises: a first upper battery sub-module and a first lower battery sub-module;

[0009] The second battery module comprises: a second upper battery sub-module and a second lower battery sub-module;

[0010] The second end of the first upper battery sub-module is connected to the second end of the second lower battery sub-module;

[0011] The first end of the resonance device is connected to the second end of the first upper battery sub-module;

[0012] The second end of the resonance device is connected to the second end of the second upper battery sub-module.

[0013] In the implementation process, the battery pack is divided into a first battery module and a second battery module, the battery capacity of the first battery module and the second battery module is equal, the first battery module comprises a first upper battery submodule and a first lower battery submodule, the second battery module comprises a second upper battery submodule and a second lower battery submodule, the first upper battery submodule and the first lower battery submodule are connected to each other, the second upper battery submodule and the second lower battery submodule are connected to each other, and the two ends of the resonance device are connected to the midpoint of the first battery module and the midpoint of the second battery module respectively. Compared with the same capacity battery self-heating circuit in the prior art, the circuit can reduce the voltage borne by the power switch in the resonance device.

[0014] Further, the first end of the first upper battery submodule and the first end of the second upper battery submodule are high-voltage ends.

[0015] The first end of the first lower battery submodule and the first end of the second lower battery submodule are low-voltage ends.

[0016] The capacity of the first upper battery submodule is greater than the capacity of the first lower battery submodule.

[0017] The capacity of the second upper battery submodule is less than the capacity of the second lower battery submodule.

[0018] In the implementation process, the capacity of the first upper battery submodule is greater than the capacity of the first lower battery submodule, and the capacity of the second upper battery submodule is less than the capacity of the second lower battery submodule, so that a voltage difference is formed between the first end and the second end of the resonance device.

[0019] Further, the ratio of the capacity of the first upper battery submodule to the capacity of the first lower battery submodule is a first ratio.

[0020] The ratio of the capacity of the second lower battery submodule to the capacity of the second upper battery submodule is a second ratio.

[0021] The first ratio and the second ratio are equal.

[0022] In the implementation process, the design method makes the temperature rise rates of the first upper battery submodule, the first lower battery submodule, the second upper battery submodule and the second lower battery submodule consistent, and the entire battery pack is uniformly heated.

[0023] Further, the first ratio and the second ratio are (1+α):(1-α), where 0<α<1.

[0024] In the implementation process, the design manner makes the temperature rising rates of the first upper battery sub-module, the first lower battery sub-module, the second upper battery sub-module and the second lower battery sub-module consistent, and the entire battery pack is uniformly heated.

[0025] Further, the resonant device comprises:

[0026] inductance, capacitance, power switch, first switch;

[0027] The first end of the inductance is connected with the second end of the first upper battery sub-module;

[0028] The second end of the inductance is connected with the first end of the capacitance;

[0029] The power switch and the capacitance are connected in parallel;

[0030] The second end of the capacitance is connected with the second end of the second upper battery sub-module through the first switch.

[0031] In the implementation process, ZVS soft switching of the power switch can be realized, the switching frequency is improved, and good electromagnetic compatibility is achieved. Through high-frequency switching of the power switch, high-frequency current can be generated in the resonant device, and the high-frequency current flows through the battery to make the battery heat and rise in temperature due to internal resistance.

[0032] Further, the resonant device comprises:

[0033] diode;

[0034] The anode of the diode is connected with the second end of the capacitance;

[0035] The cathode of the diode is connected with the first end of the capacitance.

[0036] Further, the first switch is composed of one or more of a relay, a fuse.

[0037] Further, the capacitance is a film capacitor.

[0038] Further, the battery self-heating circuit further comprises: a second switch and a third switch;

[0039] The first end of the first upper battery sub-module is connected with the high-voltage end of the direct-current bus of the vehicle through the second switch;

[0040] The second end of the first lower battery sub-module is connected with the low-voltage end of the direct-current bus.

[0041] In a second aspect, the embodiments of the present application provide a vehicle comprising the battery self-heating circuit of the first aspect.

[0042] In the implementation process, the battery pack is divided into a first battery module and a second battery module, the battery capacity of the first battery module and the second battery module is equal, the first battery module comprises a first upper battery submodule and a first lower battery submodule, the second battery module comprises a second upper battery submodule and a second lower battery submodule, the first upper battery submodule and the first lower battery submodule are connected to each other, the second upper battery submodule and the second lower battery submodule are connected to each other, and the two ends of the resonance device are connected to the midpoint of the first battery module and the midpoint of the second battery module respectively. Compared with the battery self-heating circuit with the same capacity in the prior art, the circuit can make the voltage borne by the power switch in the resonance device lower.

[0043] Other features and advantages of the present application will be described in the following description, or can be inferred from the description, or can be determined without doubt, or can be known by implementing the above-mentioned technology of the present application.

[0044] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the following preferred embodiments are specifically described, and the accompanying drawings are described in detail as follows. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments of the present application. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0046] Figure 1 The structural schematic diagram of the battery self-heating circuit provided by the embodiments of the present application is shown in the figure.

[0047] Figure 2 Another structural schematic diagram of the battery self-heating circuit provided by the embodiments of the present application is shown in the figure.

[0048] Figure 3 Another structural schematic diagram of the battery self-heating circuit provided by the embodiments of the present application is shown in the figure.

[0049] Figure legend: 1-first battery module; 2-second battery module; 3-resonance device; 11-first upper battery submodule; 12-first lower battery submodule; 21-second upper battery submodule; 22-second lower battery submodule; 31-power switch; 32-capacitor; 33-inductor; 34-first switch; 35-diode; 4-second switch; 5-third switch. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

[0051] It should be noted that similar reference numbers and letters represent similar items in the drawings below, and therefore, once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings. Meanwhile, in the description of the present application, the terms "first", "second", etc. are only used for distinguishing description, and cannot be understood as indicating or implying relative importance.

[0052] Embodiment 1

[0053] Referring to Figure 1 The embodiments of the present application provide a battery sub-heating circuit, comprising: a battery pack; a resonance device 3; the battery pack comprises: a first battery module 1, a second battery module 2;

[0054] The resonance device 3 comprises: a power switch 31, and the resonance device 3 is used for generating a frequency current for heating the battery pack based on the opening and closing of the power switch 31;

[0055] The first battery module 1 comprises: a first upper battery submodule 11 and a first lower battery submodule 12;

[0056] The second battery module 2 comprises: a second upper battery submodule 21 and a second lower battery submodule 22;

[0057] The second end of the first upper battery submodule 11 is connected to the second end of the second lower battery submodule 22;

[0058] The first end of the resonance device 3 is connected to the second end of the first upper battery submodule 11;

[0059] The second end of the resonance device 3 is connected to the second end of the second upper battery submodule 21.

[0060] In the implementation process, the battery pack is divided into the first battery module 1 and the second battery module 2, the battery capacity of the first battery module 1 and the second battery module 2 is equal, the first battery module 1 comprises: the first upper battery submodule 11 and the first lower battery submodule 12, the second battery module 2 comprises: the second upper battery submodule 21 and the second lower battery submodule 22; the first upper battery submodule 11 and the first lower battery submodule 12 are connected to each other; the second upper battery submodule 21 and the second lower battery submodule 22 are connected to each other; the two ends of the resonance device 3 are connected to the midpoint of the first battery module 1 and the midpoint of the second battery module 2, respectively. Compared with the same capacity battery self-heating circuit in the prior art, the circuit can reduce the voltage borne by the power switch 31 in the resonance device 3.

[0061] Preferably, the battery capacity of the first battery module 1 and the second battery module 2 is equal.

[0062] Further, the first end of the first upper battery submodule 11 and the first end of the second upper battery submodule 21 are high-voltage ends;

[0063] The first end of the first lower battery submodule 12 and the first end of the second lower battery submodule 22 are low-voltage ends;

[0064] The capacity of the first upper battery submodule 11 is greater than the capacity of the first lower battery submodule 12;

[0065] The capacity of the second upper battery submodule 21 is less than the capacity of the second lower battery submodule 22.

[0066] In the above implementation process, the capacity of the first upper battery submodule 11 is greater than the capacity of the first lower battery submodule 12; and the capacity of the second upper battery submodule 21 is less than the capacity of the second lower battery submodule 22, so that a voltage difference is formed between the first end and the second end of the resonant device 3.

[0067] Further, the ratio of the capacity of the first upper battery submodule 11 to the capacity of the first lower battery submodule 12 is a first ratio;

[0068] The ratio of the capacity of the second lower battery submodule 22 to the capacity of the second upper battery submodule 21 is a second ratio;

[0069] The first ratio and the second ratio are equal.

[0070] In the above implementation process, the design makes the temperature rise rates of the first upper battery submodule 11, the first lower battery submodule 12, the second upper battery submodule 21, and the second lower battery submodule 22 consistent, and the entire battery pack is uniformly heated.

[0071] Further, the first ratio and the second ratio are (1+α):(1-α), where 0<α<1.

[0072] In the above implementation process, the design makes the temperature rise rates of the first upper battery submodule 11, the first lower battery submodule 12, the second upper battery submodule 21, and the second lower battery submodule 22 consistent, and the entire battery pack is uniformly heated.

[0073] Further, the resonant device 3 comprises:

[0074] The inductor 33, the capacitor 32, the power switch 31, the first switch 34, and the diode 35;

[0075] The first end of the inductor 33 is connected to the second end of the first upper battery submodule 11;

[0076] The second end of the inductor 33 is connected to the first end of the capacitor 32;

[0077] The power switch 31 and the capacitor 32 are connected in parallel;

[0078] The second end of the capacitor 32 is connected through the first switch 34 and the second end of the second upper battery submodule 21;

[0079] The anode of the diode 35 is connected with the second end of the capacitor 32;

[0080] The cathode of the diode 35 is connected with the first end of the capacitor 32.

[0081] In the above implementation process, the ZVS soft switching of the power switch 31 can be realized, the switching frequency is improved, and good electromagnetic compatibility is achieved. Through the high-frequency switching of the power switch 31, the resonant device can generate a high-frequency current, and the high-frequency current flows through the battery to heat and warm up the battery due to the internal resistance.

[0082] Further, the first switch 34 is composed of one or more of a relay, a fuse.

[0083] Further, the capacitor 32 is a thin film capacitor.

[0084] Further, the battery self-heating circuit further comprises: a second switch 4 and a third switch 5;

[0085] The first end of the first upper battery submodule 11 is connected through the second switch 4 and the high-voltage end of the direct-current bus of the vehicle;

[0086] The second end of the first lower battery submodule 12 is connected with the low-voltage end of the direct-current bus.

[0087] When the battery needs to be heated, the second switch 4 and the third switch 5 are opened, the first switch 34 is closed, and the opening and closing of the power switch 31 is controlled according to a certain switching frequency and a certain duty ratio PWM, so that the power switch 31 is in the ZVS soft switching state, so that the resonant circuit composed of the capacitor 32 and the inductor 33 can maintain stable resonance and generate alternating current, thereby heating the battery. If heating is not required, the power switch 31 or the first switch 34 can be disconnected.

[0088] It should be noted that when the power switch 31 is accidentally damaged and short-circuited, the battery midpoint will be short-circuited. Therefore, at this time, the first switch 34 can be disconnected to play a protective role. If heating is not required, the power switch 31 is disconnected to stop working, and the resonant circuit becomes an open-circuit safe state.

[0089] Based on the above embodiment, the working principle of the circuit is described, and the beneficial effects of the embodiment of the application are further embodied.

[0090] Referring to Figure 2 , according to the proportional relationship of the battery combination, the circuit can be simplified as Figure 2 , wherein U1=U4=(1-α) / 2*UBat , U2=U3=(1+α) / 2*U Bat ; Z1=Z4=(1-α)Z Bat , Z2=Z3=(1+α)Z Bat ; U1, U2, U3, U4 are the voltages of the first upper battery submodule 11, the first lower battery submodule 12, the second upper battery submodule 21, and the second lower battery submodule 22, respectively, U Bat is the voltage of the battery pack. Z1, Z2, Z3, and Z4 are the impedances of the first upper battery submodule 11, the first lower battery submodule 12, the second upper battery submodule 21, and the second lower battery submodule 22, respectively. Bat is the impedance of the battery pack. Figure 2 Model, calculation can be obtained I1=I2=I3=I4=I r / 2, I1, I2, I3, and I4 are the current magnitudes of the first upper battery submodule 11, the first lower battery submodule 12, the second upper battery submodule 21, and the second lower battery submodule 22, respectively, and Ir is the resonant current in the resonant device 3. Since the power battery pack can be considered to be composed of identical single battery cells connected in series, the same current flowing through the first upper battery submodule 11, the first lower battery submodule 12, the second upper battery submodule 21, and the second lower battery submodule 22 means that the same current flows through each single battery cell. This ensures that the heating power of each single battery cell is consistent, and therefore the heating rate will also be basically consistent.

[0091] When the battery self-heating circuit is working, using the circuit Thevenin theorem, it can be simplified to Figure 3 Equivalent circuit; at this time, the four battery cells are equivalent to a voltage source U E and an internal resistance, U E =αU BAt , where U BAt is the voltage of the battery pack; during the operation of the resonant circuit, the voltage on the capacitor 32 is proportional to U E This voltage is also the highest voltage that the power switch needs to withstand. Therefore, by lowering α, the highest voltage on the capacitor 32 can be reduced, thereby reducing the withstand voltage requirement of the power switch 31.

[0092] Example 2

[0093] An embodiment of the present application provides a vehicle, comprising the battery self-heating circuit of embodiment 1.

[0094] The above merely provides an example of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and thus, once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings.

[0095] The above merely provides an example of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and thus, once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings.

[0096] It should be noted that the relational terms herein such as first and second and the like are used solely to distinguish one from another entity or action without necessarily requiring or implying any actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

Claims

1. A battery self-heating circuit, characterized by, The battery self-heating circuit comprises: a battery pack; a resonance device; the battery pack comprises: a first battery module, a second battery module; the resonance device comprises: a power switch, and the resonance device is used to generate a frequency current to heat the battery pack based on the opening and closing of the power switch; the first battery module comprises: a first upper battery sub-module and a first lower battery sub-module; the second battery module comprises: a second upper battery sub-module and a second lower battery sub-module; a first end of the resonance device is connected to a second end of the first upper battery sub-module; a second end of the resonance device is connected to a second end of the second upper battery sub-module; a battery capacity of the first battery module is equal to a battery capacity of the second battery module; a first end of the first upper battery sub-module and a first end of the second upper battery sub-module are high-voltage ends; a first end of the first lower battery sub-module and a first end of the second lower battery sub-module are low-voltage ends; a capacity of the first upper battery sub-module is greater than a capacity of the first lower battery sub-module; and a capacity of the second upper battery sub-module is less than a capacity of the second lower battery sub-module; the resonance device comprises: an inductor, a capacitor, a power switch, a first switch, and a diode; a first end of the inductor is connected to a second end of the first upper battery sub-module; a second end of the inductor is connected to a first end of the capacitor; the power switch and the capacitor are connected in parallel; a second end of the capacitor is connected to a second end of the second upper battery sub-module through the first switch; an anode of the diode is connected to the second end of the capacitor; a cathode of the diode is connected to the first end of the capacitor.

2. The battery self-heating circuit according to claim 1, wherein: a ratio of the capacity of the first upper battery sub-module to the capacity of the first lower battery sub-module is a first ratio; a ratio of the capacity of the second lower battery sub-module to the capacity of the second upper battery sub-module is a second ratio; the first ratio is equal to the second ratio.

3. The battery self-heating circuit of claim 2, wherein, the first ratio and the second ratio are (1+α):(1-α), where 0<α<1.

4. The battery self-heating circuit of claim 1, wherein, the first switch is composed of one or more of a relay and a fuse.

5. The battery self-heating circuit of claim 4, wherein, the capacitor is a film capacitor.

6. The battery self-heating circuit of claim 1, wherein, the battery self-heating circuit further comprises: a second switch and a third switch; a first end of the first upper battery sub-module is connected to a high-voltage end of a direct-current bus of a vehicle through the second switch; a second end of the first lower battery sub-module is connected to a low-voltage end of the direct-current bus.

7. A vehicle characterized by comprising: the battery self-heating circuit comprises any one of claims 1-6.

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