A centralized charging device and method for lithium batteries in a low temperature environment

Abstract

The present invention discloses a centralized charging device and method for lithium batteries in a low temperature environment, comprising a heat preservation box, a Z-shaped operation panel, a first heating device and a second heating device, wherein the Z-shaped operation panel is fixed in the heat preservation box, the first heating device comprises a first silicone heating film and a support plate, the first silicone heating film is arranged on the upper side of the support plate, the support plate is fixed below the upper plane of the Z-shaped operation panel through a mounting column, the second heating device comprises a second silicone heating film and a partition, the second silicone heating film is arranged on the upper side of the lower plane of the Z-shaped operation panel, and the partition is fixed above the lower plane of the Z-shaped operation panel through a mounting column. The present invention can centrally charge lithium batteries of various models and specifications, and can automatically maintain the box in a temperature range suitable for lithium battery charging through a temperature control unit, and maintain a uniform temperature in the box.

Description

Technical Field

[0001] The present invention relates to a charging device and method, in particular to a centralized charging device and method for lithium batteries in a low-temperature environment, belonging to the technical field of charging devices. Background Art

[0002] At present, the characteristics of lithium batteries are significantly affected by their working environment. Especially at low temperatures, the electrochemical reaction activity of lithium batteries is reduced, and their available capacity and charge and discharge performance decay seriously. Low-temperature charging may cause lithium ion precipitation and accumulation, seriously affecting the service life of lithium batteries, causing irreversible damage, and even causing safety accidents.

[0003] Battery low-temperature heating technology mainly refers to a series of heating measures taken in a low-temperature environment to improve the battery's charging and discharging performance and extend the battery life. For the characteristics of lithium batteries, excessively hot and cold external temperatures will greatly reduce the battery charging efficiency and pose safety risks. This requires that the lithium battery charging device can quickly heat up to a suitable temperature under low-temperature conditions to provide an external heating environment for battery charging, but it is not advisable to make the internal temperature of the charging unit too high. Existing methods generally heat the battery through an external heat source, such as using a heating belt, a heater, or placing the battery in a heated environment. Or use the characteristics of phase change materials (PCM) to absorb or release heat during the phase change process to adjust the internal temperature of the battery charging unit.

[0004] The above method can provide an internal temperature environment for the charging device, but there is a possibility of local overheating. In addition, the existing technology ignores the monitoring of the internal temperature environment of the box, which will cause the user to be unable to accurately grasp the internal temperature of the charging unit box, which is easy to cause safety hazards.

[0005] In addition, the existing military chargers are unable to charge multiple types of batteries in a centralized manner due to the different battery models, and the various compatible charging devices are also relatively single in adaptability to charging batteries. There are no reports on the development of charging units that can centrally charge batteries at low temperatures. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a centralized charging device and method for lithium batteries in a low temperature environment, which can realize centralized charging guarantee for batteries of various models and ensure that the internal temperature is suitable for charging lithium batteries.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] A centralized charging device for lithium batteries in a low-temperature environment comprises a heat preservation box, a Z-shaped operating panel, a first heating device and a second heating device. The Z-shaped operating panel is fixed in the heat preservation box. The first heating device comprises a first silicone heating film and a support plate. The first silicone heating film is arranged on the upper side of the support plate. The support plate is fixed below the upper plane of the Z-shaped operating panel through a mounting column. The second heating device comprises a second silicone heating film and a partition. The second silicone heating film is arranged on the upper side of the lower plane of the Z-shaped operating panel. The partition is fixed above the lower plane of the Z-shaped operating panel through a mounting column.

[0009] Furthermore, the heat preservation box body comprises a lower box body and an upper cover, the rear side of the upper cover is hinged to the rear side of the lower box body, and the front side of the upper cover is detachably connected to the front side of the lower box body via a butterfly buckle.

[0010] Furthermore, a handle is provided on the front side of the lower box.

[0011] Furthermore, a temperature display screen and a light emitting module are provided on the front side of the upper cover.

[0012] Furthermore, an AC input interface is provided on the side of the upper cover, a plurality of 12V interfaces, a plurality of 36V interfaces and a plurality of USB interfaces are provided on one side of the upper plane of the Z-shaped operation panel, and a plurality of thermocouples are also provided on the upper side of the Z-shaped operation panel.

[0013] Furthermore, it also includes an AC / DC rectifier module, which is fixed in the inner cavity of the sealed box below the upper plane of the Z-shaped operation panel.

[0014] Furthermore, it also includes a fan, with an air inlet on one side of the lower box body and an air outlet on the other side of the lower box body. The fan is fixed on the inner side of the air outlet of the lower box body, and a detachable fan cover is provided on the outer side of the air inlet and the air outlet.

[0015] Furthermore, it also includes a temperature control unit, which includes a temperature switch K1, a temperature switch K2, a temperature switch K3 and a bypass switch K4. The operating temperature value of the temperature protection of the temperature switch K1 is 0°C~40°C, the operating temperature value of the temperature protection of the temperature switch K2 is 40°C, and the operating temperature value of the temperature protection of the temperature switch K3 is 0°C. The light-emitting module includes a resistor R1, a rectifier diode D2 and a light-emitting diode D1. One end of the start switch SB is connected to the AC L line, and the other end of the start switch SB is connected to one end of the temperature display screen, one end of the temperature switch K1, one end of the temperature switch K3 and one end of the bypass switch K4. The other end of the temperature switch K1 is connected to one end of the temperature switch K2. The other end of the temperature switch K2 is connected to one end of the heating device and one end of the resistor R1, the other end of the resistor R1 is connected to the cathode of the rectifier diode D2 and the anode of the light-emitting diode D1, the other end of the temperature switch K3 is connected to the other end of the bypass switch K4 and the first input end of the AC / DC rectifier module, the 36V output end of the AC / DC rectifier module is connected to multiple 36V interfaces, the 12V output end of the AC / DC rectifier module is connected to multiple 12V interfaces, the 5V output end of the AC / DC rectifier module is connected to multiple USB interfaces, and the other end of the temperature display screen, the other end of the heating device, the anode of the rectifier diode D2, the cathode of the light-emitting diode D1 and the second input end of the AC / DC rectifier module are connected.

[0016] A method for centralized charging of lithium batteries in a low-temperature environment, based on a centralized charging device for lithium batteries in a low-temperature environment, comprises the following steps:

[0017] When the initial external environment temperature is lower than 0℃, the charging device is connected to AC power, the start switch SB is closed, the temperature switch K1 and the temperature switch K2 are closed, the heating device works to heat up the environment inside the box, and the light-emitting diode D1 is lit; when the temperature inside the box rises to above 0℃, the temperature switch K3 is automatically closed, the charging circuit starts to work, and the battery is charged; when the temperature inside the box rises to above 40℃, the temperature switch K1 and the temperature switch K2 are automatically disconnected, the heating device loses power and stops working, the light-emitting diode D1 is extinguished, and the charging circuit maintains a normal working state to charge the battery;

[0018] When the initial external environment temperature is between 0℃ and 40℃, the charging device is connected to AC power, the start switch SB is closed, the temperature switch K1, the temperature switch K2 and the temperature switch K3 are automatically closed, at this time, the heating device in the entire charging device works, the light-emitting diode D1 lights up, the charging circuit starts to work, and the battery is charged; when the heating device raises the temperature of the box environment to above 40℃, the temperature switch K1 and the temperature switch K2 are automatically disconnected, the heating device loses power and stops working, the light-emitting diode D1 goes out, and the charging circuit maintains a normal working state to charge the battery;

[0019] When the initial external ambient temperature is above 40°C, the charging device is connected to AC power, the start switch SB is closed, the fan cover is opened, the cooling fan starts running, the temperature switch K1 and the temperature switch K2 are automatically disconnected, the light-emitting diode D1 is off, and the temperature switch K3 is automatically closed. At this time, only the charging circuit in the entire charging device starts working to charge the battery.

[0020] Compared with the prior art, the present invention has the following advantages and effects: the present invention provides a centralized charging device and method for lithium batteries in a low-temperature environment, which can centrally charge lithium batteries of various models and specifications, and is easy to operate and simple in structure; the present invention can automatically maintain the temperature inside the box in a temperature range suitable for charging the lithium batteries through a temperature control unit, so that the user can clearly know the temperature inside the box, and the temperature control unit has a simple structure and low cost, that is, it realizes automatic turning on and off of the heating function to maintain a uniform temperature inside the box. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of a centralized charging device for lithium batteries in a low temperature environment of the present invention.

[0022] Figure 2 It is a schematic diagram of an open state of a low-temperature environment lithium battery centralized charging device of the present invention.

[0023] Figure 3 It is an internal schematic diagram of a low-temperature environment lithium battery centralized charging device of the present invention.

[0024] Figure 4 The invention discloses a control circuit diagram of a centralized charging device for lithium batteries in a low temperature environment. DETAILED DESCRIPTION

[0025] In order to elaborate on the technical scheme adopted by the present invention to achieve the predetermined technical purpose, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only partial embodiments of the present invention, rather than all embodiments, and the technical means or technical features in the embodiments of the present invention can be replaced without paying creative work. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0026] like Figure 1 and Figure 2As shown, a centralized charging device for lithium batteries in a low-temperature environment of the present invention comprises a heat preservation box 1, a Z-shaped operating panel 2, a first heating device and a second heating device. The six inner surfaces of the heat preservation box 1 are all provided with a heat preservation layer, so as to facilitate heat insulation of the interior in extremely cold weather. The Z-shaped operating panel 2 is fixed in the heat preservation box 1. The Z-shaped operating panel 2 is composed of an upper plane, a vertical panel and a lower plane. The upper plane and the lower plane are both arranged in the horizontal direction. The vertical panel is arranged vertically and the upper side of the vertical panel is fixedly connected to one side of the upper plane, and the lower side of the vertical panel is fixedly connected to one side of the lower plane. The height of the vertical panel is consistent with the height of the lower box in the heat preservation box 1. After installation, the upper plane is flush with the upper plane of the lower box, and the lower plane is supported on the inner bottom surface of the heat preservation box 1. In this way, a relatively closed cavity space is formed between the upper plane, the vertical panel and the insulation box body 1, which is used to install the internal components of the charging device, and a groove space with an open upper side is formed between the vertical panel, the lower plane and the insulation box body 1, and the lithium battery to be charged can be placed in the groove space.

[0027] like Figure 3 As shown, the first heating device includes a first silicone heating film 3 and a support plate 4, wherein the first silicone heating film 3 is arranged on the upper side of the support plate 4, and the support plate 4 is fixed below the upper plane of the Z-shaped operating panel 2 by means of a mounting column 5, and the second heating device includes a second silicone heating film 6 and a partition 7, wherein the second silicone heating film is arranged on the upper side of the lower plane of the Z-shaped operating panel, and the partition is fixed above the lower plane of the Z-shaped operating panel by means of a mounting column. Since the charger and the lithium battery need to be placed on the Z-shaped operating panel 2, in order to avoid directly heating the lithium battery, the first heating device of the present invention is installed on the support plate, and the upper side of the second heating device is separated by a partition, so that there is a certain space between the two silicone heating films and the use interface, so as to avoid direct contact with the shell or the use interface, and heat is exchanged with the surrounding air by heat conduction, so as to realize the heat circulation in the whole heat preservation box 1.

[0028] The silicone heating film can also be replaced by a positive temperature coefficient thermistor heater.

[0029] like Figure 1 and 2 As shown, the heat preservation box 1 comprises a lower box 8 and an upper cover 9, the rear side of the upper cover 9 is hinged to the rear side of the lower box 8, and the front side of the upper cover 9 is detachably connected to the front side of the lower box 8 via a butterfly buckle 10. The interior of the upper cover 9 bulges upward, so that a large accommodating space can be formed between the inner side of the upper cover 9 and the upper plane of the Z-shaped operation panel 2 to place various types of lithium batteries for charging.

[0030] A handle 11 is provided on the front side of the lower box body 8, and the handle 11 can be used to conveniently move the charging device, which is suitable for outdoor use.

[0031] The front side of the upper cover 9 is provided with a temperature display screen 12 and a light emitting module 13. The temperature display screen 12 can display the temperature inside the heat preservation box 1 in real time. Since the heat preservation box 1 needs to be in a closed state during charging, the temperature display screen 12 is installed on the outside of the heat preservation box 1, and can display the internal temperature in real time, so that the user can know the internal working conditions of the heat preservation box 1 in a timely manner. The light emitting module 12 is used to prompt whether it is in a heating state, so that the user can know the internal charging state and situation in a timely manner.

[0032] The side of the upper cover 9 is provided with an AC input interface 14, which can be directly connected to an AC power source such as a mains or a portable field generator through the AC input interface 14. One side of the upper plane of the Z-shaped operation panel 2 is provided with multiple 12V interfaces 15, multiple 36V interfaces 16 and multiple USB interfaces 17, which are adapted to the input voltage of military battery chargers, 18650 chargers, mobile phones and other communication devices. The upper side of the Z-shaped operation panel 2 is also provided with multiple thermocouples 18, and the data collected by the thermocouples 18 is displayed through the temperature display screen 12.

[0033] like Figure 3 As shown, a low-temperature environment lithium battery centralized charging device of the present invention also includes an AC / DC rectifier module 19, which is fixed in the inner cavity of the sealed box 1 below the upper plane of the Z-shaped operating panel 2. The input range of the AC / DC rectifier module is 90V~264V, 4Hz~63Hz, and it can output 36V, 12V, and 5V DC voltages respectively for charging other chargers or mobile phones. The AC / DC rectifier module 19 can use an integrated rectifier module with three voltage outputs, or it can use three rectifier modules with different voltage outputs separately.

[0034] The low-temperature environment lithium battery centralized charging device of the present invention further comprises a fan, an air inlet is opened on one side of the lower box 8, an air outlet is opened on the other side of the lower box 8, the fan is fixed on the inner side of the air outlet of the lower box 8, and a detachable fan cover 20 is arranged on the outer side of the air inlet and the air outlet. When the temperature in the sealed box 1 is too high, the fan cover 20 on the air inlet and the air outlet is opened, and the fan is started to dissipate heat in the sealed box 1. When the temperature is not high, the fan cover 20 remains closed to ensure the sealing and heat preservation performance of the sealed box 1 as a whole.

[0035] The low temperature environment lithium battery centralized charging device of the present invention further comprises a temperature control unit, such as Figure 4As shown, the temperature control unit includes a temperature switch K1, a temperature switch K2, a temperature switch K3 and a bypass switch K4. The action temperature value of the temperature protection of the temperature switch K1 is 0℃~40℃, that is, it remains closed when the temperature in the box is lower than 0℃, and remains disconnected when the temperature in the box is higher than 40℃; the action temperature value of the temperature protection of the temperature switch K2 is 40℃, that is, it remains closed when the temperature in the box is lower than 40℃, and remains disconnected when the temperature in the box is higher than 40℃; the action temperature value of the temperature protection of the temperature switch K3 is 0℃, which is disconnected below 0℃ and closed above 0℃. The light-emitting module includes a resistor R1, a rectifier diode D2 and a light-emitting diode D1, one end of a start switch SB is connected to an AC L line, the other end of the start switch SB is connected to one end of a temperature display screen, one end of a temperature switch K1, one end of a temperature switch K3 and one end of a bypass switch K4, the other end of the temperature switch K1 is connected to one end of a temperature switch K2, the other end of the temperature switch K2 is connected to one end of a heating device and one end of the resistor R1, the other end of the resistor R1 is connected to a cathode of the rectifier diode D2 and an anode of the light-emitting diode D1, the other end of the temperature switch K3 is connected to the other end of the bypass switch K4 and a first input end of an AC / DC rectifier module, the 36V output end of the AC / DC rectifier module is connected to a plurality of 36V interfaces, the 12V output end of the AC / DC rectifier module is connected to a plurality of 12V interfaces, the 5V output end of the AC / DC rectifier module is connected to a plurality of USB interfaces, the other end of the temperature display screen, the other end of the heating device, the anode of the rectifier diode D2, the cathode of the light-emitting diode D1 and the second input end of the AC / DC rectifier module are connected. When the temperature is lower than 0℃, the AC / DC rectifier module has no output due to the disconnection of the temperature switch K3, so that the military charger, 18650 charger and USB output module connected after the AC / DC rectifier module cannot work below 0℃. In an emergency, when the battery needs to be charged below 0℃, the user can close the bypass switch K4 to make the military charger, 18650 charger and USB output module work at low temperature to charge the battery. The rectifier diode D2 and the light-emitting diode D1 are connected in series in reverse. When the AC voltage is positive, the rectifier tube D2 is cut off, and the light-emitting diode D1 is forward-conducted and emits light normally, and the rectifier tube D2 is clamped at the same time. When the AC is reversed, the rectifier tube D2 is turned on, and the light-emitting diode D1 is clamped at the same time. The light-emitting diode D1 is fixed to the outer shell panel of the charging unit. When the system is in the heating state, the light-emitting diode D1 lights up, and the user can clearly know that the system is in the heating state.

[0036] A temperature switch is a device used to measure and control or detect temperature. It can open or close the circuit when the preset temperature is reached, thereby controlling the temperature. The temperature switch can be made of metal components, which will deform when heated, thereby driving the electrical contacts to operate. This device uses a temperature switch, the main function of which is to control and maintain the safe operation of the circuit within the preset temperature range. It can avoid the harm of the circuit to the battery charging caused by the high or low ambient temperature, and ensure the normal charging state of the military lithium battery.

[0037] The temperature switch K1 and the temperature switch K2 can also be replaced by a temperature relay or other temperature controller.

[0038] The present invention adopts three independently arranged AC / DC rectifier modules, wherein the first AC / DC rectifier module outputs a voltage of 36V, and is connected to a military battery charger through a quick-plug interface, and the quick-plug interface has a working status indicator light, the second AC / DC rectifier module outputs a voltage of 12V, and is connected to a 18650 charger through a quick-plug interface, and the third AC / DC rectifier module outputs a voltage of 5V, and is connected to a USB output interface through a quick-plug interface. The military charger and the 18650 battery charger can be designed as charging card holders embedded in the charging unit operation panel, and connected to the output ends of the three AC / DC rectifier modules through internal wiring. It can also be designed as an independent pluggable charging seat, and the output end connectors of the three AC / DC rectifier modules are fixed on the charging unit operation panel, and the extended quick-plug interfaces of the military charger and the 18650 battery charger are quickly connected to the output interface fixed on the charging unit operation panel. It is convenient to charge the battery centrally.

[0039] A method for centralized charging of lithium batteries in a low-temperature environment, based on a centralized charging device for lithium batteries in a low-temperature environment, comprises the following steps:

[0040] When the initial external environment temperature is lower than 0℃, the charging device is connected to AC power, the start switch SB is closed, the temperature switch K1 and the temperature switch K2 are closed, the heating device works to heat up the environment inside the box, and the light-emitting diode D1 is lit; when the temperature inside the box rises to above 0℃, the temperature switch K3 is automatically closed, the charging circuit starts to work, and the battery is charged; when the temperature inside the box rises to above 40℃, the temperature switch K1 and the temperature switch K2 are automatically disconnected, the heating device loses power and stops working, the light-emitting diode D1 is extinguished, and the charging circuit maintains a normal working state to charge the battery;

[0041] When the initial external environment temperature is between 0℃ and 40℃, the charging device is connected to AC power, the start switch SB is closed, the temperature switch K1, the temperature switch K2 and the temperature switch K3 are automatically closed, at this time, the heating device in the entire charging device works, the light-emitting diode D1 lights up, the charging circuit starts to work, and the battery is charged; when the heating device raises the temperature of the box environment to above 40℃, the temperature switch K1 and the temperature switch K2 are automatically disconnected, the heating device loses power and stops working, the light-emitting diode D1 goes out, and the charging circuit maintains a normal working state to charge the battery;

[0042] When the initial external ambient temperature is above 40°C, the charging device is connected to AC power, the start switch SB is closed, the fan cover is opened, the cooling fan starts running, the temperature switch K1 and the temperature switch K2 are automatically disconnected, the light-emitting diode D1 is off, and the temperature switch K3 is automatically closed. At this time, only the charging circuit in the entire charging device starts working to charge the battery.

[0043] The present invention provides a device and method for centralized charging of lithium batteries in a low-temperature environment, which can perform centralized charging of lithium batteries of various models and specifications, and has convenient operation and simple structure. The present invention can automatically maintain the temperature inside the box in a temperature range suitable for charging the lithium batteries through a temperature control unit, so that the user can clearly know the temperature inside the box, and the temperature control unit has a simple structure and low cost, that is, it realizes automatic turning on and off of the heating function, and maintains a uniform temperature inside the box.

[0044] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement made to the above embodiments without departing from the content of the technical solution of the present invention, based on the technical essence of the present invention, within the spirit and principles of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims

1. A low temperature environment lithium battery centralized charging device, characterized in that: The heat preservation box comprises a heat preservation box, a Z-shaped operation panel, a first heating device and a second heating device, wherein the Z-shaped operation panel is fixed in the heat preservation box, the first heating device comprises a first silicone heating film and a support plate, the first silicone heating film is arranged on the upper side of the support plate, the support plate is fixed below the upper plane of the Z-shaped operation panel through a mounting column, the second heating device comprises a second silicone heating film and a partition, the second silicone heating film is arranged on the upper side of the lower plane of the Z-shaped operation panel, and the partition is fixed above the lower plane of the Z-shaped operation panel through a mounting column; The heat preservation box body comprises a lower box body and an upper cover, the rear side of the upper cover is hinged to the rear side of the lower box body, and the front side of the upper cover is detachably connected to the front side of the lower box body through a butterfly buckle; It also includes a temperature control unit, which includes a temperature switch K1, a temperature switch K2, a temperature switch K3 and a bypass switch K4. The operating temperature value of the temperature protection of the temperature switch K1 is 0°C~40°C, the operating temperature value of the temperature protection of the temperature switch K2 is 40°C, and the operating temperature value of the temperature protection of the temperature switch K3 is 0°C. The light-emitting module includes a resistor R1, a rectifier diode D2 and a light-emitting diode D1. One end of the start switch SB is connected to the AC L line, and the other end of the start switch SB is connected to one end of the temperature display screen, one end of the temperature switch K1, one end of the temperature switch K3 and one end of the bypass switch K4. The other end of the temperature switch K1 is connected to one end of the temperature switch K2. The other end of K2 is connected to one end of the heating device and one end of the resistor R1, the other end of the resistor R1 is connected to the cathode of the rectifier diode D2 and the anode of the light-emitting diode D1, the other end of the temperature switch K3 is connected to the other end of the bypass switch K4 and the first input end of the AC / DC rectifier module, the 36V output end of the AC / DC rectifier module is connected to multiple 36V interfaces, the 12V output end of the AC / DC rectifier module is connected to multiple 12V interfaces, the 5V output end of the AC / DC rectifier module is connected to multiple USB interfaces, the other end of the temperature display screen, the other end of the heating device, the anode of the rectifier diode D2, the cathode of the light-emitting diode D1 and the second input end of the AC / DC rectifier module are connected.

2. A low temperature environment lithium battery centralized charging device according to claim 1, characterized in that: A handle is provided on the front side of the lower box.

3. A low temperature environment lithium battery centralized charging device according to claim 1, characterized in that: A temperature display screen and a light emitting module are arranged on the front side of the upper cover.

4. A low temperature environment lithium battery centralized charging device according to claim 1, characterized in that: An AC input interface is arranged on the side of the upper cover, a plurality of 12V interfaces, a plurality of 36V interfaces and a plurality of USB interfaces are arranged on one side of the upper plane of the Z-shaped operation panel, and a plurality of thermocouples are also arranged on the upper side of the Z-shaped operation panel.

5. The low temperature environment lithium battery centralized charging device according to claim 1, characterized in that: It also includes an AC / DC rectifier module, which is fixed in the inner cavity of the sealed box below the upper plane of the Z-shaped operation panel.

6. The low temperature environment lithium battery centralized charging device according to claim 1, characterized in that: It also includes a fan, with an air inlet on one side of the lower box body and an air outlet on the other side of the lower box body. The fan is fixed on the inner side of the air outlet of the lower box body, and a detachable fan cover is provided on the outer side of the air inlet and the air outlet.

7. A method for centralized charging of lithium batteries in a low temperature environment, based on the centralized charging device for lithium batteries in a low temperature environment according to any one of claims 1 to 6, characterized in that The following steps are involved: When the initial external environment temperature is lower than 0℃, the charging device is connected to AC power, the start switch SB is closed, the temperature switch K1 and the temperature switch K2 are closed, the heating device works to heat up the environment inside the box, and the light-emitting diode D1 is lit; when the temperature inside the box rises to above 0℃, the temperature switch K3 is automatically closed, the charging circuit starts to work, and the battery is charged; when the temperature inside the box rises to above 40℃, the temperature switch K1 and the temperature switch K2 are automatically disconnected, the heating device loses power and stops working, the light-emitting diode D1 is extinguished, and the charging circuit maintains a normal working state to charge the battery; When the initial external environment temperature is between 0℃ and 40℃, the charging device is connected to AC power, the start switch SB is closed, the temperature switch K1, the temperature switch K2 and the temperature switch K3 are automatically closed, at this time, the heating device in the entire charging device works, the light-emitting diode D1 lights up, the charging circuit starts to work, and the battery is charged; when the heating device raises the temperature of the box environment to above 40℃, the temperature switch K1 and the temperature switch K2 are automatically disconnected, the heating device loses power and stops working, the light-emitting diode D1 goes out, and the charging circuit maintains a normal working state to charge the battery; When the initial external ambient temperature is above 40°C, the charging device is connected to AC power, the start switch SB is closed, the fan cover is opened, the cooling fan starts running, the temperature switch K1 and the temperature switch K2 are automatically disconnected, the light-emitting diode D1 is off, and the temperature switch K3 is automatically closed. At this time, only the charging circuit in the entire charging device starts working to charge the battery.

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