TW201725824A - Battery preheating system comprising a first battery set, a second battery set, a current limiter, a first switch module, a second switch module, and a charge and discharge controller - Google Patents

Abstract

A battery preheating system comprises a first battery set and a second battery set which are connected in series; a current limiter connected in series with the first battery set and a first switch module for forming a first charge and discharge circuit, the current limiter being further connected in series with the second battery set and a second switch module for forming a second charge and discharge circuit; and a charge and discharge controller electrically connected to the first and second battery sets and the first and second switch modules for detecting battery characteristics of the first and second battery sets and alternatively controlling on/off of the first and second switch modules. The first and second switch modules perform turn-onor turn-off operation to limit flow direction of the current flowing therethrough. The current limiter further stores or consumes the current that flows in, so as to limit flow of the current. As such, the current can flow between the first and second battery sets and the current limiter for charging and discharging, and the battery characteristics of the first and second battery sets can be detected for controlling the switch, so as to achieve the battery preheating effect.

Description

Battery preheating system

The present invention relates to a preheating circuit system for a battery, and more particularly to a battery preheating system that can discharge and charge between different batteries and current limiters.

With the evolution of technology and environmental problems, in addition to the existing electronic devices or electronic devices that use batteries, the technology of batteries has been transferred to vehicles, resulting in the growth of many two- or four-wheel electric vehicles. Its own energy supply source, when the energy in the battery is exhausted, then replace the battery or charge the battery to make up the energy consumed.

In recent years, because many electronic devices or electric vehicles have to face a very low temperature environment due to latitude or environmental problems, in this environment, the ion mobility of the electrolyte inside the battery decreases, and the impedance rises, which is not suitable. General battery charging or high current discharge. At this time, if the electric vehicle or the like is directly charged, it is likely to cause a permanent increase in the impedance of the battery and an increase in polarization, which may result in a decrease in the battery capacity, a rapid deterioration of the performance, and the like, in particular, the lithium battery is at a low temperature. Improper charging can result in reduced service life and the formation of a negative tip, thus creating many safety issues for subsequent charging.

Therefore, many battery designers, in addition to the compatibility of the battery specifications with the device, gradually invented many battery preheating circuit designs or methods, but the general battery preheating circuit is by external heating device. Increasing the temperature of the battery has many thermal conduction limitations and safety considerations, while increasing the space, weight and cost of the device. Even if the temperature-increasing circuit is designed inside the battery, it only reveals how to improve the temperature of the battery itself through the design of the circuit. It does not disclose the overall heating circuit and how to judge the internal temperature rise of the battery to reach the method of stopping the heating condition. Increasing the temperature of the battery may pose a higher risk to the user and the device or device in which the battery is installed.

Therefore, in view of the problem of low-temperature charging of the conventional battery, the present invention provides a battery preheating system, in addition to continuously charging and discharging each other by individual batteries to raise the temperature, and continuously monitoring the internal temperature or impedance of the battery, when two Heating can be stopped after one of the presets reaches the preset range.

The main object of the present invention is to provide a battery preheating system, which is controlled by two sets of batteries and their corresponding switches, and switches between the batteries and the current limiter in a periodic manner and in a very short time. The current is charged and discharged, and the battery is rapidly charged and discharged by the current to gradually increase the temperature of each battery, so that the temperature of each battery can be effectively raised before the battery is charged and discharged at a low temperature. To avoid charging and discharging the battery at low temperatures, it will damage the battery itself.

Another object of the present invention is to provide a battery preheating system, which can detect whether the temperature of each battery reaches a preset value by detecting the temperature or impedance value of each battery, thereby avoiding excessive heating of the battery, and causing the battery temperature to exceed the standard. The device that damages the battery or installs its battery, so that the present invention can more effectively control the heating of the battery.

A further object of the present invention is to provide a battery preheating system, which can detect the voltage value of each battery, and can detect the voltage value of each battery. When the voltage values of the two batteries are different, the control can be controlled. Switching cycle of the switch to avoid causing the voltage of any battery to exceed the standard, or even if the voltage values of the two batteries are different at the beginning, the switching cycles of different switches can be used to control the charging and discharging times of the two batteries, thereby protecting the battery and A device that installs its battery.

In order to achieve the above object, the present invention provides a battery preheating system including a first battery pack, a second battery pack, a first switch module, a second switch module, a current limiter, and a charge and discharge. Controller. The first battery module and the second battery module are connected in series, the first switch module is electrically connected to the first battery pack and the second switch module is electrically connected to the second battery pack, the first switch module and the second switch module The current can be turned on or off, and the flow of current flowing through is limited, and the current limiter is connected in series with the first battery pack and the first switch module to form a first charge and discharge circuit, and the current limiter and the second battery pack And the second switch module is connected in series to form a second charge and discharge circuit, and the current limiter can store or consume the inflow current and limit the current flow flowing. The charge and discharge controller is electrically connected to the first battery pack, the second battery pack, the first switch module and the second switch module, and can detect battery characteristic values in the first battery pack and the second battery pack, and Controlling the battery characteristic value to alternately control the opening or closing of the first switch module and the second switch module, and causing a flow of charge and discharge current between the first battery pack, the current limiter and the second battery pack, When the battery characteristic values in the first battery pack and the second battery pack are detected to a preset value, the first switch module and the second switch module are turned off to stop the flow of the charging and discharging current. [00010] When the first battery pack as described above charges and discharges the current limiter, the current flow direction when the second battery pack charges and discharges the current limiter is opposite. [00011] The first battery pack as described above further includes at least one first battery and a first resistor, the first battery can release and receive the charging and discharging current, and the first resistor is connected in series with the at least one first battery, the first resistor The temperature reduction impedance value can be increased by the charge and discharge current discharged or received by the at least one first battery; the second battery pack further includes at least one second battery and a second resistor, and the second battery can release and receive the charge The current is discharged, and the second resistor is connected in series with the at least one second battery, and the second resistor can increase the temperature reduction impedance value by the charge and discharge current released or received by the at least one second battery. [00012] The battery preheating system as described above further includes at least one second inductor coupled to the inductor, and at least one second inductor is connected in parallel to the inductor and serially connected to the first battery pack and the first Between the switch modules, and in series between the second battery pack and the second switch module, by designing the inductance value of the second inductor, the current flow limiting the power back to the battery can be adjusted. [0001] The battery preheating system further includes at least four diodes connected in series to the at least one second inductor and the first switch module or the at least one second inductor and the second switch module. At least four or two pole systems can limit the flow of charge and discharge current. [00014] The first switch module further includes a first switch and a first diode. The first switch is connected in series between the first battery pack and the current limiter, and the first switch can be turned on or off. The first diode is connected in parallel with the first switch, and is connected in series between the first battery pack and the current limiter. The first two-pole system can limit the current flow flowing through; the second switch module further includes a first a second switch and a second diode, the second switch is connected in series between the second battery pack and the current limiter, the second open relationship can be opened or closed, the second diode is connected in parallel with the second switch, and is connected in series Between the second battery pack and the current limiter, the second diode system can limit the flow of current flowing through. [00015] The charge and discharge controller as described above can simultaneously detect voltage differences in the first battery pack and the second battery pack to respectively control the number of times the first switch module and the second switch module are turned on or off. [00016] The purpose, technical content, features, and effects achieved by the present invention are more readily understood by the detailed description of the embodiments.

[00018] The battery preheating system of the present invention can increase and control the temperature of the battery to an appropriate temperature by current flowing in the two sets of batteries to avoid improper charging of the battery in a low temperature environment, and charging and discharging. The controller can further control the switching period of the switch according to the voltage difference of each battery, so that the voltage of each battery reaches a dynamic average. [00019] First, referring to the first figure of the present invention, a battery preheating system 10 includes a first battery pack 12, a second battery pack 14, a first switch module 16, and a second switch. The module 18, a current limiter 20 and a charge and discharge controller 22, in the present embodiment, the current limiter 20 is an inductor. The first battery module 12 and the second battery unit 14 are connected in series, the first switch module 16 is electrically connected to the first battery pack 12, and the second switch module 18 is electrically connected to the second battery pack 14, the current limiter 20 The first battery pack 12 and the first switch module 16 are connected in series to form a first charge and discharge circuit CL1, and the current limiter 20 is further connected in series with the second battery pack 14 and the second switch module 18 to form a The second charging and discharging circuit CL2; the charging and discharging controller 22 is electrically connected to the first battery pack 12, the second battery pack 14, the first switch module 16, and the second switch 18 module. [00020] Next, each element in the first battery pack 12, the second battery pack 14, the first switch module 16, and the second switch module 18 and their connection relationship will be described in more detail. The first battery pack 12 includes at least one first battery 122 and a first resistor 124 connected in series. In this embodiment, the first battery 122 is exemplified by one; the second battery pack 14 includes at least one second battery 142 and A second resistor 144 is connected in series. In the embodiment, the second battery 142 is exemplified by one. The first switch module 16 includes a first switch S1 and a first diode D1. The first switch S1 is connected in series. Connected between the first resistor 124 and the current limiter 20 in the first battery pack 12, the first diode D1 is connected in parallel to the first switch S1, and is connected in series to the first resistor 124 and the current limit in the first battery pack 12. The second switch module 18 includes a second switch S2 and a second diode D2. The second switch S2 is connected in series to the negative pole and the current limiter of the second battery 142 in the second battery pack 14. 20, the second diode D2 is connected in parallel with the second switch S2, and is connected in series between the negative electrode of the second battery 142 in the second battery pack 14 and the current limiter 20, which is the first two in this embodiment. The polar body D1 and the second diode D2 are Schottky diodes. [00021] After receiving the above paragraph, after explaining the structure of the battery preheating system 10 of the present invention and the component connection relationship therein, the method of performing battery preheating of the battery preheating system 10 of the present invention, the first battery pack 12 and the second battery will be described next. The group 14 can respectively charge and discharge the current limiter 20, and the battery characteristic values of the first battery pack 12 and the second battery pack 14 are detected by the charge and discharge controller 22, and the battery characteristic value is the temperature in this embodiment. And the impedance value, the charge and discharge controller 22 further detects the temperature of the first battery pack 12 and the second battery pack 14 by using the detected battery characteristic value, and then alternately controls the first switch module 16 and The second switch module 18 performs on or off, and causes a flow of charge and discharge current between the first battery pack 12, the current limiter 20 and the second battery pack 14. The current limiter 20 is provided with a current limiting flow rate and a current limit. The function of increasing and decreasing rate, when the current limiter has an inductance characteristic, it stores the current flowing in to limit the rate of increase or decrease of the current flow flowing out; when the current limiter has a resistance characteristic, it Consumption of energy flows and restrict the flow of current into or out of. And detecting the voltage difference between the first battery pack 12 and the second battery pack 14 to control the number of times the first switch module 16 and the second switch module 18 are turned on or off, respectively, when detecting the first battery pack 12 And when the battery characteristic value in the second battery pack 14 reaches a preset value, for example, the heating temperature reaches a preset temperature value, or the internal temperature rise of the corresponding battery is obtained because the impedance value is lowered to a preset value. When the switch is high, the first switch module 16 and the second switch module 18 are closed to open the flow of the charge and discharge current, and the first battery pack 12 charges and discharges the current limiter 20 in the first charge and discharge circuit CL1. The charge and discharge current is opposite to the flow of the charge and discharge current that the second battery pack 14 charges and discharges to the current limiter 20 in the second charge and discharge circuit CL2. [00022] After the preheating method of the present invention is described, the actual operation mode of the present invention will be described in detail by way of an embodiment, but it should not be limited by this embodiment. For example, please refer to the second and second B diagrams of the present invention, and refer to the third figure at the same time. In the second diagram, the charge and discharge controller 22 detects the first battery pack 12 and the second battery pack. 14 When the temperature before charging is too low, the first switch module 16 may be first controlled to close the first switch S1 to form an on state T1A, so that the first battery 122 in the first battery pack 12 can be opposite to the current limiter 20 Charging so that the stored current I _L in the current limiter 20 rises, and the negative (discharge) current I ₁ in the first battery 122 increases, when the charged current I _L reaches a preset value, In the second diagram, the first switch S1 is turned on to form an open state T1B. At this time, the current stored in the current limiter 20 is transferred to the second battery pack 14 and stored in the second battery 142 via the second resistor 144. In order to cause the stored current I _L in the current limiter 20 to drop, equivalent to the forward charging current I ₂ in the second battery 142 is converted into a form of chemical energy for storage. Next, please refer to the second C diagram and the second diagram of the present invention, and refer to the third diagram at the same time. In the second C diagram, the charge and discharge controller 22 controls the second switch module 18 to turn off. The second switch S2 is configured to form an on state T2A such that the second battery 142 in the second battery pack 14 can charge the current limiter 20 to cause the stored current I _L in the current limiter 20 to exhibit an inverse rise. The negative (discharge) current I ₂ in the second battery 142 is increased. When the charged current I _L reaches a preset value, the second switch S2 is turned on in the second D diagram to form an open state T2B. The current I _L stored in the current limiter 20 is transmitted to the first battery pack 12 via the first diode D1 in the first switch module 16 and then to the first battery 122 via the first resistor 124. The storage is converted to chemical energy such that the stored reverse current I _L (equivalent to the charging current I ₁ in the first battery 122 ) in the current limiter 20 is reduced, and is instead stored in the form of chemical energy. the first battery, the direction indicated I _L C of the second D view and FIG among the second and the second a and second B in FIG. FIG. Trans, T2A therefore in a conducting state and an open state of FIG third period of the current I _L T2B is negative. After the reciprocating cycle, the currents I ₁ , I _L , and I ₂ are caused to flow in the first battery pack 12, the second battery pack 14, and the current limiter 20, so that the currents I ₁ and I ₂ continuously flow through the first resistor. The first resistor 124 and the second resistor 144 can generate heat and reduce the impedance value due to an increase in temperature, thereby heating the first battery pack 12 and the second battery pack 14 to be heated until When the charge and discharge controller 22 detects that the first battery pack 12 and the second battery pack 14 reach a certain temperature or has a specific impedance value, the charge and discharge controller 22 turns on the first switch S1 and the second switch S2 to form an open circuit. At this time, the heating is stopped, and the user can set the maximum temperature or the minimum impedance of the required heating, which can be designed according to different environments and different battery specifications, and the present invention does not limit the heating temperature. [00023] The present invention further provides another embodiment. Referring to the fourth embodiment of the present invention, the current limiter 20' in the battery preheating system 10' may be an inductor L1 and at least a second inductor. L2 is coupled. In this embodiment, an inductor L1 is coupled to a second inductor L2, and the second inductor L2 is connected in parallel to the inductor L1, and is electrically connected to the first battery pack 12 and the first switch. The modules 16 and the second inductor L2 are electrically connected between the second battery pack 14 and the second switch module 18. Further, the method further includes at least four diodes. In this embodiment, the third diode D3, the fourth diode D4, the fifth diode D5, and the sixth diode D6 are taken as an example, and the third diode D3 is used. The fourth diode D4, the fifth diode D5, and the sixth diode D6 are Schottky diodes, and the third diode D3 and the fourth diode D4 are electrically connected to the second diode D3, respectively. The second inductor L2, the first battery pack 12 and the first switch module 16, the fifth diode D5 and the sixth diode D6 are electrically connected to the second inductor L2 and the second battery pack 14, respectively. The second switch module 18 is between. The fourth figure of the present invention differs from the first figure in the inductance of the inductor in the current limiter 20' and the current limiter 20. Both the inductor L1 and the second inductor L2 can limit the current flow flowing out, and more The third diode D3, the fourth diode D4, the fifth diode D5, and the sixth diode D6 limit the flow of the charging and discharging current, and the main control is still detected by the charge and discharge controller 22. a battery characteristic value of the battery pack 12 and the second battery pack 14 to control the opening or closing of the first switch module 16 and the second switch module 18 to cause charging and discharging current to the first battery pack 12 and the current limiter 20, flowing between the current limiter 20' and the second battery pack 14, and generating heat to the first resistor 124 in the first battery pack 12 and the second resistor 144 in the second battery pack 14, when the first battery pack 12 When the battery characteristic value of the second battery pack 14 reaches a preset value, the charge and discharge controller 22 turns on the first switch module 16 and the second switch module 18 to open the circuit to stop heating. Because the inductances of the mutual coupling inductors 20, 20' are different, the waveform timing diagram generated by the fourth figure can be referred to the fifth figure of the present invention, which avoids charging of a large current to the first battery pack 12. The second battery 142 of the first battery 122 and the second battery pack 14 is damaged. The inductor is mainly used as a current for reducing charging, and the user can design the inductance of the coupled inductor according to the battery specification. [00024] Thus, the battery preheating system of the present invention can be preheated, whether it is an inductor or recoupled to at least one inductor, and stops heating when the temperature or impedance value in the battery pack reaches a certain value. Next, the present invention will be described in detail how the temperature of the battery pack rises by the impedance value of the battery pack. Please refer to FIG. 6A of the present invention and refer to FIG. 2A, FIG. 2B, and FIG. The second D picture. When the first switch S1 is turned on, the current of the current I ₁ loop continues to increase, and the current I ₁ at this time corresponds to the stored current I _L in the current limiter 20, and the terminal voltage V1 of the first battery pack 12 at this time. When the second switch S2 is turned on, the current of the current I ₂ loop will continue to increase. At this time, the current I ₂ corresponds to the current I _L in the current limiter 20 , but the current I ₂ flows to the current I ₁ loop. On the contrary, therefore, the current I _L at this time is a negative value, and the terminal voltage V2 of the second battery pack 14 also drops. The following is a description of the actual values. The sixth diagram is a waveform diagram before the battery pack is warmed up. For example, the impedances of the first battery pack 12 and the second battery pack 14 are both 0.25 ohms and the voltage is 20 volts. The exemplary values of the present embodiment should not be limited thereto. When the first switch S1 is turned on, the current I ₁ (equivalent current I _L ) rises from 0 to 32 amps, at which time the voltage drop of the first resistor 124 is 32 amps multiplied by 0.25 ohms equals 8 volts. Therefore, at this time, the terminal voltage V1 of the first battery pack 12 is lowered from the original 20 volts to 12 volts. Similarly, during the second switch S2 being turned on, the second battery pack 14 may also have the same situation. Next, referring to the sixth b diagram of the present invention and referring to the second A diagram, the second B diagram, the second C diagram, and the second diagram D, after the first battery pack 12 and the second battery pack 14 are warmed up, The impedance value is 0.1 ohm. When the first switch S1 is turned on, the current I ₁ (equivalent current I _L ) rises from 0 to 36 amps, and the voltage drop of the first resistor 124 is 36 amps multiplied by 0.1 ohms. 3.6 volts. Therefore, at this time, the terminal voltage V1 of the first battery pack 12 is lowered from the original 20 volts to 16.4 volts. Similarly, during the second switch S2 being turned on, the second battery pack 14 may also have the same situation. When the first resistor 124 of the first battery pack 12 and the second resistor 144 of the second battery pack 14 are lowered, whether the first battery pack 12 or the second battery pack 14 is turned on when the first switch S1 or the second switch S2 is turned on. The amplitude of the voltage drop is significantly reduced. Therefore, the decrease in the resistance value means that the battery is preheated at a low temperature, and the battery can be preheated from the change of the voltage value, and the resistance value and the voltage value are changed as the preheating degree. Judge. [00025] The first battery pack and the second battery pack in the embodiment of the first or fourth embodiment described above take a battery as an example, and assumes that each battery pack has the same voltage and performs charging of each battery. The discharge and discharge controller disclosed in the present invention can detect the voltage difference between the first battery pack and the second battery pack during charging and discharging to control the switches of the first switch module and the second switch module. When it is found that the difference in the amount of electricity between the first battery pack and the second battery pack continues to expand, the charge and discharge controller controls the length of the switch and the number of times of the first switch module or the second switch module, resulting in the first battery pack and One of the second battery packs has a larger amount of energy to transfer a larger amount of energy to another set of battery packs, so that the first battery pack and the second battery pack can maintain a balanced battery capacity without one of them. The battery pack is overloaded or insufficient due to heating. Similarly, the present invention can also be applied to a first battery pack and a second battery pack that are connected in series with different battery numbers to preheat the two battery packs. For example, when the first battery pack is connected in series with three batteries, and the second battery pack is connected in series with five batteries, when the charge and discharge controller detects the difference in power, the first switch module and the second switch module are The switching frequency is controlled to maintain the amount of power that the first battery pack and the second battery pack should have. Therefore, in any of the above cases, the charge and discharge controller must detect the difference in the amount of electricity between the first battery pack and the second battery pack before the end of the warm-up procedure, by adjusting the first switch module and the second switch module. The switching frequency is adjusted to adjust the difference in the capacity of the first battery pack and the second battery pack to an acceptable range. With the long-term use of the battery pack, the difference in the amount of electricity between the first battery pack and the second battery pack may gradually increase, resulting in a decrease in the usable capacity of the two battery packs in series. In this case, even if the battery pack itself does not have the requirement of preheating, the difference between the power levels of the battery packs can be adjusted to an acceptable range by the first switch module and the second switch module. [00026] In summary, the battery preheating system of the present invention mainly preheats the battery pack in a low temperature environment, so that the battery pack does not have improper charging, and can control the temperature of the battery pack heating. It does not cause safety problems due to overheating or low temperature charging of the battery pack, and can effectively protect the battery pack and the equipment for installing the battery pack, thereby further protecting the safety of the user. The invention does not limit the battery pack specifications and the battery packs that need to be connected in series, and the user can design the same, the resistance in the battery pack can be regarded as the internal resistance in the battery pack, or the internal resistance in the battery pack cannot be effectively generated. In the case of thermal energy, the user can separately connect the resistors. The main spirit of the present invention is to charge and discharge the two battery packs to preheat the respective battery packs, and to control the power consumption of each battery pack and the final stop. Heat the timing to effectively protect the battery pack. The embodiments described above are merely illustrative of the technical spirit and features of the present invention, and are intended to enable those skilled in the art to understand the present invention and practice the present invention. The scope of the patent, i.e., the equivalent variations or modifications made by the spirit of the invention, should still be covered by the scope of the invention.

【00028】
10‧‧‧Battery preheating system
10'‧‧‧Battery preheating system
12‧‧‧First battery pack
122‧‧‧First battery
24‧‧‧First resistance
14‧‧‧Second battery pack
142‧‧‧second battery
144‧‧‧second resistance
16‧‧‧First switch module
18‧‧‧Second switch module
20‧‧‧ Current limiter
20'‧‧‧ Current Limiter
22‧‧‧Charge and discharge controller
CL1‧‧‧First charge and discharge circuit
CL2‧‧‧Second charge and discharge circuit
D1‧‧‧First Diode
D2‧‧‧ second diode
D3‧‧‧ third diode
D4‧‧‧ fourth diode
D5‧‧‧ fifth diode
D6‧‧‧ sixth diode
I ₁ ‧‧‧ Current
I ₂ ‧‧‧current
I _L ‧‧‧current
L1‧‧‧Inductors
L2‧‧‧second inductor
T1A‧‧‧ conduction status
T1B‧‧‧ Open circuit status
T2A‧‧‧ conduction status
T2B‧‧‧ Open circuit status
V1‧‧‧ terminal voltage
V2‧‧‧ terminal voltage
S1‧‧‧ first switch
S2‧‧‧ second switch

[00017] The first figure is a schematic diagram of a circuit architecture of a first embodiment of the present invention. 2A and 2B are schematic diagrams showing the operation of the first switch module in the first embodiment of the present invention. The second C diagram and the second D diagram are schematic diagrams of the operation of the second switch module in the first embodiment of the present invention. The third figure is a waveform timing chart of the first embodiment of the present invention. The fourth figure is a schematic diagram of a circuit architecture of a second embodiment of the present invention. Fig. 5 is a waveform timing chart of the second embodiment of the present invention. Figure 6A is a waveform timing diagram of the battery pack of the present invention before it is warmed up. The sixth B is a waveform timing diagram of the battery pack of the present invention after preheating.

10‧‧‧Battery preheating system

12‧‧‧First battery pack

122‧‧‧First battery

124‧‧‧First resistance

14‧‧‧Second battery pack

142‧‧‧second battery

144‧‧‧second resistance

16‧‧‧First switch module

18‧‧‧Second switch module

20‧‧‧ Current limiter

22‧‧‧Charge and discharge controller

CL1‧‧‧First charge and discharge circuit

CL2‧‧‧Second charge and discharge circuit

D1‧‧‧First Diode

D2‧‧‧ second diode

S1‧‧‧ first switch

S2‧‧‧ second switch

Claims (12)

A battery preheating system includes: a first battery pack and a second battery pack, wherein the first battery pack and the second battery pack are connected in series; a first switch module and a second switch module, The first switch module is electrically connected to the first battery pack and the second switch module is electrically connected to the second battery pack, and the first switch module and the second switch module are turned on or off, and Limiting the current flow through the current; a current limiter connected in series with the first battery pack and the first switch module to form a first charge and discharge circuit, and the second battery pack and the first The two switch modules are connected in series to form a second charge and discharge circuit, the current limiter can store or consume the inflow current to limit the current flow in and out; and a charge and discharge controller electrically connected to the first a battery pack, the second battery pack, the first switch module, and the second switch module, wherein the charge and discharge controller detects battery characteristic values in the first battery pack and the second battery pack, and Alternatingly controlling the battery characteristic value detected by the battery Turning on or off a switch module and the second switch module, and causing a flow of charge and discharge current between the first battery pack, the current limiter and the second battery pack, when detecting the first battery pack And when the battery characteristic value in the second battery pack reaches a predetermined value, the first switch module and the second switch module are turned off to stop the flow of the charging and discharging current. The battery preheating system according to claim 1, wherein when the first battery pack charges and discharges the current limiter, the current flow direction when the second battery pack charges and discharges the current limiter is opposite. The battery preheating system of claim 1, wherein the battery characteristic value is a temperature and an impedance value. The battery preheating system of claim 1, wherein the first battery pack further comprises: at least one first battery that can release and receive the charging and discharging current; and a first resistor that is coupled to the at least one The first battery is connected in series, and the first resistor can increase the temperature reduction impedance value by the charging and discharging current released or received by the at least one first battery. The battery preheating system of claim 4, wherein the second battery pack further comprises: at least one second battery that can release and receive the charging and discharging current; and a second resistor that is coupled to the at least one The second battery is connected in series, and the second resistor can increase the temperature reduction impedance value by the charging and discharging current released or received by the at least one second battery. The battery preheating system of claim 1, wherein the current limiter is an inductor or a resistor. The battery preheating system of claim 6, further comprising: at least one second inductor coupled to the inductor, wherein the at least one second inductor is connected in parallel to the inductor, and is electrically connected to Between the first battery pack and the first switch module, and electrically connected between the second battery pack and the second switch module, the second inductor can limit the current flow flowing out; And the quadrupole is electrically connected to the at least one second inductor, the first battery pack and the first switch module, and the other two of the diodes are electrically connected to the at least one The quadrupole system, the second battery pack and the second switch module, the quadrupole system can limit the flow of the charging and discharging current. The battery preheating system of claim 7, wherein the at least four-pole system is a Schottky diode. The battery preheating system of claim 1, wherein the first switch module further comprises: a first switch connected in series between the first battery pack and the current limiter, the first open relationship Opened or closed; and a first diode connected in parallel to the first switch and connected in series between the first battery and the current limiter, the first two-pole system can limit the flow Current flow. The battery preheating system of claim 9, wherein the second switch module further comprises: a second switch connected in series between the second battery pack and the current limiter, the second open relationship Opened or closed; and a second diode connected in parallel to the second switch and connected in series between the second battery pack and the current limiter, the second diode system can limit the flow Current flow. The battery preheating system of claim 10, wherein the first diode and the second diode system are Schottky diodes. The battery preheating system of claim 1, wherein the charge and discharge controller can simultaneously detect a voltage difference between the first battery pack and the second battery pack to separately control the first switch module and the The number of times the second switch module is turned on or off.