CN112590553A

CN112590553A - Battery box, electric automobile and battery box thermal runaway control method

Info

Publication number: CN112590553A
Application number: CN202011516026.3A
Authority: CN
Inventors: 辛晓冬; 霍首星
Original assignee: China Aviation Lithium Battery Co Ltd; CALB Technology Co Ltd
Current assignee: Avic Innovation Technology Research Institute Jiangsu Co ltd; China Lithium Battery Technology Co Ltd
Priority date: 2020-12-21
Filing date: 2020-12-21
Publication date: 2021-04-02

Abstract

The invention relates to the technical field of batteries, in particular to a battery box and a thermal runaway control method of the battery box; the battery box comprises a battery unit, a cooling system, a bypass circuit, a detection unit and a control system; the cooling system is used for cooling the battery unit; the bypass circuit is connected between the battery unit and the cooling system and is provided with a bleeder switch; the detection unit is used for detecting a thermal runaway early warning parameter of the battery unit; the control system is connected with the detection unit and the bleeder switch and used for judging whether the battery unit has a thermal runaway risk according to the thermal runaway early warning parameters, so that the bleeder switch is controlled when the battery unit has the thermal runaway risk, the battery unit is made to discharge, and the discharged electric quantity is used for supplying power to the cooling system. Through the design, the invention can reduce the occurrence of thermal runaway, inhibit the spread of the thermal runaway, supply the discharged electric quantity to the cooling system, effectively utilize the discharged electric quantity and has better economical efficiency and environmental protection.

Description

Battery box, electric automobile and battery box thermal runaway control method

Technical Field

The invention relates to the technical field of batteries, in particular to a battery box, an electric automobile and a battery box thermal runaway control method.

Background

The lithium ion battery has wide markets in the fields of new energy electric automobiles, energy storage, ships, aerospace and military, but the inherent safety risk of the lithium ion battery is a key factor which troubles the application development of the lithium ion battery. Specifically, the lithium ion battery has high energy density and power density, and the materials such as the anode and the cathode in the battery, the electrolyte and the like all contain chemical sensitive substances which have high chemical activity and are easy to burn and ignite. Therefore, once the lithium ion battery is in thermal runaway, the lithium ion battery can be easily and rapidly burnt to cause fire, and then thermal spread occurs, so that the thermal runaway of the adjacent battery is caused, and the severity of the thermal runaway is further aggravated. At present, the fire accident of new energy automobiles and energy storage power stations is mostly caused by thermal runaway of a battery system.

In order to reduce the risk of thermal runaway, the safety measures adopted by the existing battery system include the modes of additionally installing a heat insulation pad, a heat conduction material, starting a cooling device and the like. However, the above-described conventional safety measures can only delay thermal runaway of the battery, and it is difficult to completely prevent thermal runaway of the battery system. In addition, the use of the heat insulation pad and the heat conduction material occupies the space of the battery system, so that the space utilization rate of the battery system is reduced, and the energy density is reduced. Moreover, the safety measures adopted by the existing battery system can only deal with the situation that the thermal runaway occurs in the battery in a single point or local position, and cannot deal with the situation that the thermal runaway occurs in a plurality of positions in the system at the same time, and cannot meet the safety control requirements of various thermal runaway modes such as short outside, short inside, short local outside, overall/local high temperature outside, mechanical abuse (needling, extrusion, falling, rolling and the like) and the like.

Disclosure of Invention

It is a primary object of the present invention to overcome at least one of the above-mentioned drawbacks of the prior art and to provide a battery case capable of effectively suppressing the propagation of thermal runaway.

In order to achieve the purpose, the invention adopts the following technical scheme:

according to an aspect of the present invention, there is provided a battery case; the battery box comprises a battery unit, a cooling system, a bypass circuit, a detection unit and a control system; the cooling system is used for cooling the battery unit; the bypass circuit is connected between the battery unit and the cooling system and is provided with a bleeder switch; the detection unit is used for detecting a thermal runaway early warning parameter of the battery unit; the control system is connected with the detection unit and the bleeder switch and used for judging whether the battery unit has a thermal runaway risk or not according to the thermal runaway early warning parameter so as to control the bleeder switch when the battery unit has the thermal runaway risk, so that the battery unit discharges electricity and the cooling system is powered by using the discharged electric quantity.

According to the technical scheme, the battery box provided by the invention has the advantages and positive effects that:

according to the battery box provided by the invention, whether the battery unit has the thermal runaway risk or not is detected by using the detection unit, and the electric quantity of the battery unit with the thermal runaway risk is discharged by controlling the on-off state of the bypass loop through the control system. Through the design, the battery box provided by the invention can reduce the occurrence of thermal runaway and can effectively inhibit the spread of the thermal runaway. In addition, the battery box provided by the invention connects the battery unit with the cooling system through the bypass loop, so that the electric quantity discharged by the battery unit can be supplied to the cooling system. Through the design, the battery box provided by the invention can effectively utilize the discharged electric quantity, is more economical and environment-friendly, and can utilize the cooling system to cool the battery unit, thereby further reducing the occurrence of thermal runaway and restraining the spread of the thermal runaway.

Another primary object of the present invention is to overcome at least one of the above-mentioned drawbacks of the prior art and to provide a thermal runaway control method for a battery box capable of effectively suppressing the propagation of a thermal runaway.

according to one aspect of the invention, a thermal runaway control method for a battery box is provided; wherein, include the following steps:

detecting a thermal runaway early warning parameter of the battery unit;

judging whether the battery unit has a thermal runaway risk or not according to the thermal runaway early warning parameter;

and discharging the battery unit with the thermal runaway risk, and supplying power to the cooling system by using the discharged electric quantity.

According to the technical scheme, the battery box thermal runaway control method has the advantages and positive effects that:

the thermal runaway control method for the battery box provided by the invention judges whether the battery unit has a thermal runaway risk or not according to the detection of the thermal runaway early warning parameter of the battery unit, and discharges the electric quantity of the battery unit with the thermal runaway risk. Through the design, the thermal runaway control method for the battery box can reduce the occurrence of thermal runaway and can effectively inhibit the spread of the thermal runaway. Through the design, the battery box thermal runaway control method provided by the invention can effectively utilize the discharged electric quantity and has better economical efficiency and environmental protection.

Another main object of the present invention is to overcome at least one of the above-mentioned drawbacks of the prior art and to provide an electric vehicle with high safety.

according to an aspect of the present invention, there is provided an electric vehicle; wherein the electric vehicle includes the battery box proposed by the present invention and described in detail in the above embodiments.

According to the technical scheme, the electric automobile provided by the invention has the advantages and positive effects that:

according to the electric automobile provided by the invention, the battery box can reduce the occurrence of thermal runaway of the battery box and effectively inhibit the spread of the thermal runaway, so that the electric automobile provided by the invention has higher safety and reliability.

Drawings

Various objects, features and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the invention, when considered in conjunction with the accompanying drawings. The drawings are merely exemplary of the invention and are not necessarily drawn to scale. In the drawings, like reference characters designate the same or similar parts throughout the different views. Wherein:

FIG. 1 is a schematic diagram of a battery box shown according to an exemplary embodiment;

FIG. 2 is a schematic illustration of a battery box according to another exemplary embodiment;

FIG. 3 is a schematic diagram of a battery box according to another exemplary embodiment;

FIG. 4 is a schematic illustration of a battery box according to another exemplary embodiment;

FIG. 5 is a schematic view of a battery box according to another exemplary embodiment;

FIG. 6 is a schematic flow diagram illustrating a battery box thermal runaway control method in accordance with an exemplary embodiment;

FIG. 7 is a schematic flow diagram illustrating a battery pack thermal runaway control method according to another exemplary embodiment;

FIG. 8 is a schematic flow diagram illustrating a battery box thermal runaway control method in accordance with another exemplary embodiment;

fig. 9 is a flowchart illustrating a battery pack thermal runaway control method according to another exemplary embodiment.

The reference numerals are explained below:

100. a battery cell;

210. a first cooling unit;

220. a second cooling unit;

300. a bypass circuit;

310. a bleeder switch;

400. a power line;

500. an electric motor.

Detailed Description

Exemplary embodiments that embody features and advantages of the invention are described in detail below. It is to be understood that the invention is capable of other and different embodiments and its several details are capable of modification without departing from the scope of the invention, and that the description and drawings are accordingly to be regarded as illustrative in nature and not as restrictive.

In the following description of various exemplary embodiments of the invention, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration various exemplary structures, systems, and steps in which aspects of the invention may be practiced. It is to be understood that other specific arrangements of parts, structures, example devices, systems, and steps may be utilized and structural and functional modifications may be made without departing from the scope of the present invention. Moreover, although the terms "over," "between," "within," and the like may be used in this specification to describe various example features and elements of the invention, these terms are used herein for convenience only, e.g., in accordance with the orientation of the examples described in the figures. Nothing in this specification should be construed as requiring a specific three dimensional orientation of structures in order to fall within the scope of the invention.

Battery box embodiment one

Referring to fig. 1, there is representatively shown a schematic view of a battery case according to the present invention. In the exemplary embodiment, the battery box according to the present invention is described as being applied to an electric vehicle. It will be readily appreciated by those skilled in the art that various modifications, additions, substitutions, deletions, or other changes may be made to the specific embodiments described below in order to adapt the inventive concepts described herein to other types of applications, such as energy storage devices, marine vessels, aerospace, military, etc., while still remaining within the scope of the principles of the battery box as set forth herein.

As shown in fig. 1, in the present embodiment, the battery box according to the present invention includes a battery unit 100, a cooling system, a bypass circuit 300, a detection unit, and a control system. Specifically, the cooling system is used to cool the battery unit 100. The bypass circuit 300 is connected between the battery unit 100 and the cooling system, and the bypass circuit 300 is provided with a bleed-off switch 310. The detection unit is used for detecting the thermal runaway early warning parameter of the battery unit 100. The control system is connected to the detection unit and the bleed-off switch 310, and is used for judging whether the battery unit 100 has a thermal runaway risk according to the thermal runaway early warning parameter, so as to control the bleed-off switch 310 when the battery unit 100 has the thermal runaway risk, for example, to control the on and off states and the opening degree of the bleed-off switch 310 (control of the discharge rate, i.e., adjustment of the electric quantity bleed-off amount and the bleed-off speed, is realized through opening degree control), which is helpful for ensuring safety, and at the same time, most of the battery units 100 can be reused, thereby avoiding unnecessary property loss. The corresponding bypass circuit 300 is turned on by closing the bleed switch 310, so that the power of the battery unit 100 is bled off through the bypass circuit 300, and the bled-off power is used to supply power to the cooling system. Through the design, the battery box provided by the invention can reduce the occurrence of thermal runaway and can effectively inhibit the spread of the thermal runaway. In addition, the battery box according to the present invention connects the battery unit 100 to the cooling system through the bypass circuit, so that the amount of power discharged from the battery unit 100 can be supplied to the cooling system. Through the design, the battery box provided by the invention can effectively utilize the discharged electric quantity, is more economical and environment-friendly, and can utilize the cooling system to cool the battery unit 100, thereby further reducing the occurrence of thermal runaway and restraining the spread of the thermal runaway.

Alternatively, in the present embodiment, the battery grouping form of the battery box may be a battery-module-Pack, a CTP (Cell to Pack, i.e., battery-Pack), or a CTC (Cell to chassis, i.e., battery-frame). Moreover, the battery system applicable to the invention is wide, and the battery system covers batteries of almost all systems, such as lithium ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries and the like with safety risks. Lithium ion batteries include, but are not limited to, organic electrolyte systems, solid state batteries, Li-S batteries, and the like. The material system comprises a lithium iron phosphate system, a lithium manganese phosphate system, a lithium vanadium phosphate system, a ternary system, a quaternary system, lithium manganate, lithium nickelate, lithium cobaltate, a cobalt-free material battery and the like.

Optionally, in this embodiment, the bypass loop may be formed by adding a bypass at a suitable position on the pole of the battery unit 100, the conductive bar of the battery box, and the power line 400, and has a simple structure, a low cost, a small space occupancy rate, and a relatively easy implementation.

Alternatively, as shown in fig. 1, in the present embodiment, the cooling system may include the first cooling unit 210, and the first cooling unit 210 may include a fan, a water cooling drain, and the like. In other embodiments, the first cooling unit 210 may also include other air cooling devices or liquid cooling devices, or both air cooling devices and liquid cooling devices, and is not limited to this embodiment. Accordingly, the battery box can supply the current discharged from the battery cell 100 to the first cooling unit 210 of the cooling system, and cool the battery cell 100 by the first cooling unit 210. With the above-described configuration, the cooling system for a battery box according to the present invention can reuse the discharged power and cool the battery unit 100 by using the first cooling unit 210 that is independent of the self-contained cooling device of the electric vehicle.

Further, as shown in fig. 1, based on the design that the cooling system includes the first cooling unit 210, in the present embodiment, the cooling system may further include the second cooling unit 220. Specifically, taking the battery box as an example for being installed in an electric vehicle, the electric vehicle includes a self-contained cooling device, which can be understood as the second cooling unit 220 of the cooling system. Accordingly, the battery box can be connected between the battery unit 100 and the on-board cooling device via the bypass circuit 300, and the power discharged from the battery unit 100 is supplied to the on-board cooling device, so that the battery unit 100 and the entire battery box (all the battery units 100) are cooled by the on-board cooling device. With the above-described configuration, the cooling system for a battery box according to the present invention can reuse the discharged electric power and cool the battery unit 100 by using the self-contained cooling device of the electric vehicle. In other embodiments, the cooling unit of the battery box according to the present invention may only include the first cooling unit 210 or only include the second cooling unit 220, and is not limited to this embodiment.

Optionally, in this embodiment, the detection unit may include a pressure sensor, and the pressure sensor is capable of detecting a pressure change rate of the battery unit 100, so that the control system can characterize the thermal runaway warning parameter of the battery unit 100 according to the pressure change rate of the battery unit. The higher the voltage change rate of the battery unit 100 is, the higher the thermal runaway warning parameter of the battery unit 100 is. In other words, when the voltage change rate of the battery cell 100 is greater than a threshold value, the battery cell 100 is at risk of thermal runaway. The battery box is convenient for collecting the voltage of the battery unit 100, and the design of representing the thermal runaway early warning parameter by adopting the voltage change rate is convenient for specific implementation and can not generate great influence on the original structure of the battery box. In other embodiments, the detection unit may also include other types of measurement devices, such as a temperature sensor, which can detect a temperature change rate of the battery unit 100, so that the control system can characterize the thermal runaway warning parameter by the temperature change rate, which is not limited to the embodiment.

In addition, in another embodiment, the thermal runaway warning parameters of the standard battery cells 100, such as the voltage difference parameter and the smoke warning information of the whole PacK system, may also be used. For example, when the voltage difference parameter of the entire Pack system is greater than a threshold, the control system controls all the battery units 100 to discharge, or further detects each battery unit 100 through other detection units to determine which one has a risk of thermal runaway, and then selects a corresponding discharge control scheme corresponding to the number and positions of the battery units 100 having the risk of thermal runaway.

Further, based on the design of representing the thermal runaway early warning parameter by using the pressure change rate of the battery unit 100, in the present embodiment, when determining whether the battery unit 100 has a thermal runaway risk, the above threshold of the voltage change rate may be 0, in other words, once the voltage change rate of the battery unit 100 is greater than 0, the control system determines that the battery unit 100 has the thermal runaway risk. Accordingly, once the voltage change rate of the battery unit 100 occurs, the control system of the battery box determines that the battery unit 100 has a thermal runaway risk, and correspondingly provides a corresponding discharge control scheme. Through the design, the battery box provided by the invention can ensure accurate and reliable judgment and control on the thermal runaway risk. In other embodiments, the threshold value of the voltage change rate for determining whether the battery cell 100 is at risk of thermal runaway may be other values greater than 0, such as 0.01mV/s, 0.05mV/s, 0.1mV/s, and the like, but is not limited to this embodiment.

It should be noted that, in various possible embodiments according to the design concept of the battery box provided by the present invention, the thermal runaway pre-warning parameter may be voltage or temperature, or may be other forms of pre-warning signals or monitoring parameters.

Alternatively, the battery box provided by the present invention may include at least two battery units 100, as shown in fig. 1, in this embodiment, the battery box includes eight battery units 100 as an example. Specifically, the eight battery cells 100 are a 1# cell, a 2# cell, a 3# cell, a 4# cell, a 5# cell, a 6# cell, a 7# cell, and an 8# cell, respectively. The positive electrode of the 1# cell is connected to the negative electrode of the 2# cell, and the positive electrode of the 2# cell is connected to the negative electrode of the 3# cell, and the connection is performed sequentially until the positive electrode of the 7# cell is connected to the negative electrode of the 8# cell. In addition, the power line 400 of the battery box is connected between the negative electrode of the 1# cell and the positive electrode of the 8# cell and the electric equipment of the electric vehicle (for example, the motor 500 of the three-phase system of the electric vehicle).

As shown in fig. 1, based on the number and layout of the battery cells 100, the battery box may include a bypass circuit in the present embodiment. Wherein the bypass circuit is connected between the cooling system and the first and last two battery units 100 (i.e., the 1# unit and the 8# unit). Specifically, the bypass circuit is connected between the first cooling unit 210 of the cooling system, the negative electrode of the 1# unit, and the positive electrode of the 8# unit. Accordingly, when detecting that there is a thermal runaway risk in any battery cell 100, the control system may control the bleed switch 310 on the bypass circuit to close, so as to conduct the bypass circuit, so that all battery cells 100 are bled by the bypass circuit and supplied to the first cooling unit 210, so that the first cooling unit 210 cools the battery box. After a period of discharging, when there is no thermal runaway risk in any battery unit 100, the control system may control the bleeding switch 310 to turn off, so as to disconnect the bypass circuit and complete the current power bleeding. Accordingly, only one bypass circuit 300 and one bleeder switch 310 need to be arranged in the battery box, and the control system only needs to control all the battery cells 100 to discharge no matter which battery cell 100 has a thermal runaway risk. Through the design, the battery box provided by the invention adopts concise circuit layout and fewer electrical switching devices, the control logic of the control system is concise and direct, and the effective control on the thermal runaway risk of the battery box can be realized.

Optionally, as shown in fig. 1, in the present embodiment, the battery box may further include another bypass loop. The bypass circuit may be directly connected to the power line 400 and the second cooling unit 220 (e.g., an on-board cooling unit of an electric vehicle). Specifically, the bypass circuit is connected between the second cooling unit 220 of the cooling system and the positive and negative poles of the power line 400. Accordingly, when it is detected that any battery unit 100 has a thermal runaway risk, the control system may selectively control such that at least one of the bleed switches 310 of the two bypass loops is closed, that is, the amount of power bled by all battery units 100 is selectively supplied to the first cooling unit 210, or supplied to the second cooling unit 220, or supplied to both the first cooling unit 210 and the second cooling unit 220. Through the design, the battery box provided by the invention can supply the discharge capacity to the self-loading cooling unit of the electric automobile, further expands the reuse range of the discharge capacity and realizes a more diversified thermal runaway risk control function. In other embodiments, based on the number and layout of the battery cells 100, the battery box may be connected to the second cooling unit 220 only by the bypass circuit, i.e., the cooling system of the battery box may include only the second cooling unit 220, which is not limited to this embodiment.

Alternatively, in the present embodiment, the control system may be, for example, a BMS system of a battery box, or the control system may be a separate control unit integrated with the BMS system.

Optionally, in this embodiment, the control system may share or join the BMS system and the big data system of the Pack, and data may be shared with each other, so as to monitor and remotely control the entire bleeding process.

Battery box embodiment two

As shown in fig. 2, which representatively shows a schematic view of a battery case according to another embodiment of the present invention. In the present embodiment, the battery box has substantially the same design as that of the first embodiment shown in fig. 1. The main differences of the battery box in this second embodiment from the above-described embodiment will be described below with reference to fig. 2.

As shown in fig. 2, in the present embodiment, the battery box may include a number of bypass circuits equal to the number of battery cells 100, in other words, one bypass circuit may be connected between each battery cell 100 and the first cooling unit 210 of the cooling system, in addition to the bypass circuit connected to the second cooling unit 220. Accordingly, when it is detected that any battery unit 100 has a risk of thermal runaway, the control system may select a corresponding control scheme according to the number and position of the battery units 100 having the risk of thermal runaway (hereinafter, referred to as target battery units), and control the bleed-off switches 310 on the corresponding bypass loops to be turned on, thereby implementing discharge of any battery unit 100, and according to different control schemes, may also implement simultaneous discharge and independent control of discharge rate of a plurality of battery units 100.

Alternatively, as shown in fig. 2, based on a design in which the battery box includes a number of bypass circuits equal to the number of battery cells 100, in the present embodiment, each of the bypass circuits may be provided with a first cooling unit 210. Accordingly, the same number of first cooling units 210 as the number of battery cells 100 may be arranged opposite to the corresponding battery cells 100, respectively, so that each battery cell 100 of the battery box has one first cooling unit 210 capable of achieving a cooling common. Through the above design, the battery box according to the present invention can cool the battery cells 100 by using separate cooling units, respectively. In other embodiments, multiple bypass circuits may also be connected to the same (or a group of) first cooling units 210 in parallel, and the present embodiment is not limited thereto.

Further, as shown in fig. 2, each of the bypass loops may share one lead connected to the positive electrode or the negative electrode of the battery cell 100 with an adjacent bypass loop in the present embodiment, based on the design in which the battery box includes the same number of bypass loops as the number of the battery cells 100. For example, the bypass circuit corresponding to the 1# cell and the bypass circuit corresponding to the 2# cell share one lead connected to the conductive connection bank of the 1# cell and the 2# cell. On this basis, the two leads of each bypass circuit connected to the positive electrode and the negative electrode of the battery unit 100 are respectively provided with a bleeder switch 310, that is, two adjacent bypass circuits share one bleeder switch 310. For example, if the 5# unit and the 4# unit share one bleed switch 310 and the 5# unit and the 6# unit share another bleed switch 310, the bypass circuit corresponding to the 5# unit has two bleed switches 310. Accordingly, the control system can control the discharge of any one of the battery cells 100 by controlling the respective bleeder switches 310. Further, the control system can select the bleeder switches 310 belonging to different bypass circuits 300 to control, thereby achieving simultaneous discharge of a plurality of battery cells 100 of a certain area.

Battery box embodiment three

As shown in fig. 3, which representatively shows a schematic view of a battery case according to another embodiment of the present invention. In the present embodiment, the battery box has substantially the same design as that of the first embodiment shown in fig. 1. The main differences of the battery box in this third embodiment from the above-described embodiments will be described below with reference to fig. 3.

As shown in fig. 3, in the present embodiment, in addition to the bypass circuit connected to the second cooling unit 220, the battery box may include two bypass circuits 300, wherein one bypass circuit 300 is connected between the cathode of the # 1 unit and the anode of the # 5 unit, and wherein the other bypass circuit 300 is connected between the cathode of the # 6 unit and the anode of the # 8 unit, so that the eight battery cells 100 are divided into two regions, i.e., two battery packs, by the two bypass circuits 300. Accordingly, the one bypass loop can be used for discharging the 1# cell, the 2# cell, the 3# cell, the 4# cell and the 5# cell, and the other bypass loop can be used for discharging the 6# cell, the 7# cell and the 8# cell. In other words, the two bypass circuits respectively cover two groups of battery packs, the two groups of battery units 100 are completely different, and the total of the two groups of battery units 100 is the total battery units 100 of the whole battery box. Accordingly, when it is detected that any battery unit 100 has a risk of thermal runaway, the control system may select a corresponding control scheme according to the level of the risk of thermal runaway, and control the battery pack in which the target battery unit is located to discharge, or control all battery packs to discharge, that is, control all battery units 100 of the battery box to discharge. Through the design, the battery box provided by the invention can utilize the bypass loop to group the battery units 100, so that the control system is used for independently controlling the discharge of the plurality of groups of battery units 100.

Battery box embodiment four

As shown in fig. 4, which representatively shows a schematic view of a battery case according to another embodiment of the present invention. In the present embodiment, the battery box has substantially the same design as that of the third embodiment shown in fig. 3. The main differences of the battery box in this fourth embodiment from the above-described embodiments will be described below with reference to fig. 4.

As shown in fig. 4, in the present embodiment, in addition to the bypass circuit connected to the second cooling unit 220, the battery box may include four bypass circuits 300, wherein one bypass circuit 300 is connected between the cathode of the 1# cell and the anode of the 2# cell, wherein another bypass circuit 300 is connected between the cathode of the 3# cell and the anode of the 4# cell, wherein another bypass circuit 300 is connected between the cathode of the 5# cell and the anode of the 6# cell, and wherein still another bypass circuit 300 is connected between the cathode of the 7# cell and the anode of the 8# cell, so that the eight battery cells 100 are divided into four regions, i.e., four battery packs, each of the battery packs includes the same number of battery cells 100, and the four battery cells 100 are completely different. Accordingly, the one bypass loop can be used for discharging the 1# cell and the 2# cell, the other bypass loop can be used for discharging the 3# cell and the 4# cell, the other bypass loop can be used for discharging the 5# cell and the 6# cell, and the other bypass loop can be used for discharging the 7# cell and the 8# cell. With the above design, based on the layout design of the bypass circuit for the divided regions of the plurality of battery cells 100, the battery box provided by the present invention can make the plurality of battery packs (regions) divided by the plurality of battery cells 100 more uniform.

Battery box embodiment five

As shown in fig. 5, which representatively shows a schematic view of a battery case according to another embodiment of the present invention. In the present embodiment, the battery box has substantially the same design as that of the third embodiment shown in fig. 3. The main differences of the battery case in this fifth embodiment from the above-described embodiments will be described below with reference to fig. 5.

As shown in fig. 5, in the present embodiment, in addition to the bypass circuit connected to the second cooling unit 220, the battery box may include three bypass circuits 300, wherein one bypass circuit 300 is connected between the cathode of the # 1 unit and the anode of the # 4 unit, wherein another bypass circuit 300 is connected between the cathode of the # 5 unit and the anode of the # 8 unit, and wherein another bypass circuit 300 is connected between the cathode of the # 3 unit and the anode of the # 6 unit, so that the eight battery units 100 are divided into three regions, i.e., three battery packs, using the three bypass circuits 300, each battery pack includes the same number of battery units 100, and four battery packs 100 are not completely identical. By "not identical" as described above, it is understood that each battery pack covers battery cells 100 that are partially identical and partially different, i.e., "not identical," from the battery cells 100 that other battery packs cover. Accordingly, the one bypass loop can be used for discharging the 1# cell, the 2# cell, the 3# cell and the 4# cell, the other bypass loop can be used for discharging the 5# cell, the 6# cell, the 7# cell and the 8# cell, and the other bypass loop can be used for discharging the 3# cell, the 4# cell, the 5# cell and the 6# cell. When any battery unit 100 has a risk of thermal runaway, the control system can select a corresponding control scheme according to the position of the target battery unit and the level of the risk of thermal runaway, and control all battery packs in which the target battery unit is located to discharge, or selectively control one of all battery packs in which the target battery unit is located to discharge, or control all battery packs to discharge, that is, control all battery units 100 of the battery box to discharge.

Further, as shown in fig. 5, in the present embodiment, each battery pack contains four battery cells 100, that is, each battery pack contains 1/2 in the number of the total number of the battery cells 100. Accordingly, by designing the number of the battery packs, it is ensured that all the battery cells 100 of the battery box can be divided into at least one battery pack, and thus, under the design scheme of the regional discharge, the discharge control of each battery cell 100 can be ensured. In other embodiments, each battery pack may also contain a number of cells 100 greater than 1/2 for the total number, and even if only two battery packs are contained, the two battery packs have partially identical cells 100. Of course, the number of the battery cells 100 included in each battery pack may be smaller than the total number of 1/2, and the number of the battery cells 100 included in each battery pack may be, but is not limited to, the same, which is not limited to this embodiment.

As described above, in some embodiments of the present invention, when the battery box includes at least three battery cells 100, at least two bypass circuits 300 may be connected between the battery cells 100 and the cooling system in a partitioned manner, so that the battery cells 100 are divided into a plurality of battery packs by being connected to different bypass circuits 300, as shown in fig. 3 to 5. The number of the battery units 100 covered by the plurality of battery packs may be the same, may not be the same, or may not be the same. Moreover, the number of the battery units 100 covered by each battery pack may be one, two, or more than two, and the battery units 100 covered by a plurality of battery packs may not be completely the same. The above "not identical" may be understood as being partially identical or not identical, i.e. "not" identical.

It should be noted herein that the battery cases shown in the drawings and described in the present specification are only a few examples of the many types of battery cases in which the principles of the present invention can be employed. It should be clearly understood that the principles of the present invention are in no way limited to any details or any components of the battery box shown in the drawings or described in this specification.

In conclusion, the invention can cover the thermal runaway safety prevention and control problem of battery systems of various material systems. The invention does not need to additionally introduce a fire extinguishing and cooling device or a flame-retardant and heat-insulating material, occupies little space, increases little weight and hardly has obvious influence on the energy density of a battery system. The invention can effectively block the occurrence of local or overall thermal runaway of the battery system, and particularly can quickly and effectively block the thermal runaway of adjacent batteries after the thermal runaway of a single battery unit occurs, thereby controlling the thermal spreading range. The invention can deal with thermal runaway and thermal spread caused by various reasons, such as thermal abuse, electrical abuse, mechanical abuse, internal short circuit and the like.

Based on the above detailed description of several exemplary embodiments of the battery box proposed by the present invention, several exemplary embodiments of the thermal runaway control method of the battery box proposed by the present invention will be described below with reference to fig. 6 to 9.

First implementation mode of thermal runaway control method for battery box

Referring to fig. 6, a flow chart of a thermal runaway control method for a battery box according to the present invention is representatively illustrated. In this exemplary embodiment, the thermal runaway control method for a battery box according to the present invention is described by taking a battery box applied to an electric vehicle as an example. It will be readily appreciated by those skilled in the art that various modifications, additions, substitutions, deletions, or other changes may be made to the embodiments described below in order to adapt the inventive concepts of the present invention to other types of applications, such as energy storage devices, marine vessels, aerospace, military, etc., while still remaining within the scope of the principles of the battery box thermal runaway control method as set forth herein.

As shown in fig. 6, in the present embodiment, the thermal runaway control method for a battery box according to the present invention includes the following steps:

detecting a thermal runaway early warning parameter of the battery unit;

Through the design, the battery box thermal runaway control method provided by the invention can effectively utilize the discharged electric quantity and has better economical efficiency and environmental protection.

Optionally, as shown in fig. 6, in this embodiment, the battery box thermal runaway control method provided by the present invention may further include a step of "cooling the battery unit by using a cooling system". Wherein, cooling system provides the electric quantity of cooling function, can be provided by the electric quantity of battery box blowdown at least partially. Through the design, the battery box thermal runaway control method provided by the invention can cool the battery unit by using the cooling system, further reduce the occurrence of thermal runaway and inhibit the spread of the thermal runaway.

Battery box thermal runaway control method implementation mode two

Fig. 7 is a schematic flow chart of a thermal runaway control method for a battery box according to another embodiment of the present invention. In the present embodiment, a battery pack thermal runaway control method is substantially the same as that of the first embodiment shown in fig. 6. The main differences of the battery box thermal runaway control method in this second embodiment from the above-described embodiments will be described below with reference to fig. 7.

Alternatively, as shown in fig. 7, in the present embodiment, when determining the risk of thermal runaway, the thermal runaway pre-warning parameter may be divided into two continuous threshold ranges, and the two threshold ranges respectively correspond to two risk levels, such as a low risk and a high risk. Accordingly, when the battery cells are controlled to discharge, the battery cells can be discharged at different discharge rates corresponding to different risk levels. For example, the battery cell may be controlled to discharge at a low discharge rate in response to a low risk, and the battery cell may be controlled to discharge at a low discharge rate in response to a high risk. Through the design, the battery box thermal runaway control method provided by the invention can correspondingly control the battery units to discharge at different discharge rates according to the severity of the thermal runaway risk of the battery units, so that the electric quantity loss of the battery box caused by excessive discharge at a lower risk level is avoided, and the thermal runaway risk is difficult to eliminate due to insufficient discharge at a higher risk level is avoided.

Alternatively, as shown in fig. 7, in the present embodiment, when the risk level is low risk while controlling the discharge of the battery cell, the target battery cell having the risk of thermal runaway may be controlled to be discharged from the adjacent other battery cells. When the risk level is a high risk, all the battery cells of the battery box may be controlled to be discharged. Through the design, the battery box thermal runaway control method provided by the invention can selectively control different numbers of battery units to discharge according to the severity of the thermal runaway risk of the battery units, so that the control requirements of a target battery unit and other adjacent battery units are ensured at low risk, and the control requirements of all battery units are ensured at high risk.

In other embodiments, regardless of whether the risk level is classified or not, or regardless of the height of the risk level, any battery cell having a risk of thermal runaway may be discharged to the target battery cell alone, may be discharged to the target battery cell and other adjacent battery cells, or may be discharged to all battery cells, which is not limited to this embodiment.

Further, based on the design of discharging at different discharge rates corresponding to different risk levels, in the present embodiment, when the battery cell is controlled to discharge, the target battery cell and the adjacent other battery cells may be controlled to discharge at a low discharge rate when the risk level is a low risk, and all the battery cells may be controlled to discharge at a high discharge rate when the risk level is a high risk.

Third implementation mode of thermal runaway control method for battery box

Fig. 8 is a schematic flow chart of a thermal runaway control method for a battery box according to another embodiment of the invention. In the present embodiment, a battery pack thermal runaway control method is substantially the same as that of the second embodiment shown in fig. 7. The main differences of the thermal runaway control method of the battery box in the three embodiments from the above embodiments will be described below with reference to fig. 8.

Alternatively, as shown in fig. 8, in the present embodiment, when determining the risk of thermal runaway, the thermal runaway pre-warning parameter may be divided into three consecutive threshold ranges, for example, a first threshold range, a second threshold range and a third threshold range from small to large, and respectively correspond to a low risk level, a medium risk level and a high risk level. Accordingly, when the battery unit is controlled to discharge, the battery unit is discharged at a first discharge rate, a second discharge rate and a third discharge rate corresponding to the low risk level, the medium risk level and the high risk level, respectively, wherein the second discharge rate is greater than the first discharge rate and less than the third discharge rate.

Further, in the present embodiment, the thermal runaway pre-warning parameter may be characterized by a voltage change rate of the battery cell. On the basis, the first threshold range can be 0-1 mV/s, namely, when the voltage change rate of the battery unit is more than 0 and less than 1mV/s, the battery unit has a low-risk-level thermal runaway risk. In other embodiments, the first threshold range may also be selected from other value ranges, i.e., the lower limit may be greater than 0, and the upper limit may be less than or greater than 1mV/s, which is not limited by the present embodiment.

Further, in the present embodiment, the thermal runaway pre-warning parameter may be characterized by a voltage change rate of the battery cell. On the basis, the second threshold value range can be 1-10 mV/s, namely, when the voltage change rate of the battery unit is more than or equal to 1mV/s and less than 10mV/s, the battery unit has the thermal runaway risk of a risk level. In other embodiments, the second threshold range may be selected from other value ranges, i.e., the lower limit may be less than or greater than 1mV/s, and the upper limit may be less than or greater than 10mV/s, which is not limited by the present embodiment.

Further, in the present embodiment, the thermal runaway pre-warning parameter may be characterized by a voltage change rate of the battery cell. In addition, the third threshold range may be 10mV/s or more, i.e., when the voltage change rate of a battery cell is 10mV/s or more, the battery cell has a high risk level of thermal runaway risk. In other embodiments, other values can be selected for the third threshold range, i.e., the lower limit can be less than or greater than 10mV/s, and is not limited by this embodiment.

Further, in the present embodiment, the first discharge rate may be 3C to 7C, for example, 3C, 4C, 5C, 7C, or the like. In other embodiments, the first discharge rate may be less than 3C, or may be greater than 7C, such as 2C, 8C, etc., and is not limited to this embodiment. In the present embodiment, the first discharge rate may be, but is not limited to, 5C.

Further, in the present embodiment, the second discharge rate may be 5C to 10C, for example, 5C, 6C, 8C, 10C, or the like. In other embodiments, the second discharge rate may be less than 5C, or may be greater than 10C, such as 4C, 11C, etc., and is not limited to this embodiment. In the present embodiment, the first discharge rate may be, but is not limited to, 7C.

Further, in the present embodiment, the third discharge rate may be 8C to 12C, for example, 8C, 10C, 11C, 12C, or the like. In other embodiments, the third discharge rate may be less than 8C, or may be greater than 12C, such as 7C, 13C, etc., and is not limited to this embodiment. In the present embodiment, the first discharge rate may be, but is not limited to, 10C.

Alternatively, as shown in fig. 8, in the present embodiment, when the battery cells are controlled to discharge, the target battery cell and the adjacent other battery cells may be controlled to discharge when the battery cells are at low risk, the target battery cell and the adjacent other battery cells may be controlled to discharge when the battery cells are at medium risk, and all the battery cells may be controlled to discharge when the battery cells are at high risk. In each risk level, each battery cell in the discharge pattern may be discharged at each discharge rate described in the present embodiment, or may be discharged at the same discharge rate, and the present embodiment is not limited thereto. Through the design, the battery unit or the battery pack in other non-adjacent areas far away from the target battery unit can be discharged, so that enough time is provided for releasing the energy of the battery unit or the battery pack in other non-adjacent areas in the heat spreading process, and the cooling system is driven to cool down, so that the thermal runaway of the battery box can be controlled within a certain degree. According to the invention, the control system can be used for carrying out electric quantity discharge on the specific battery unit and the specific battery Pack, accurate electric quantity discharge control can be carried out on a target battery unit, other adjacent battery units, other remote battery units and all battery units with thermal runaway risks, intelligent control of the battery units in a specific sequence and specific discharge multiplying power can be realized, and even if a certain string of battery units is subjected to thermal runaway, the adjacent battery strings can be kept stable after energy discharge and reuse and cannot be subjected to thermal spreading, so that the phenomena of thermal runaway fire and smoke cannot occur in the whole module and even in the Pack.

Alternatively, based on the above method design of the discharge scheme, when the battery cell is controlled to discharge, and when the risk of the battery cell is low, other battery cells adjacent to the target battery cell may be controlled to discharge at a smaller discharge rate than that of the target battery cell. On the basis, the other battery cells (except the target battery cell and the adjacent other battery cells) can be simultaneously controlled to be discharged at a minimum discharge rate smaller than the smaller discharge rate. Similarly, when the battery cells are at intermediate risk, the above-described discharge scheme may also be employed, and the discharge rate of each battery cell may be increased as a whole in accordance with the above-described magnitude relationship. When the battery units are at high risk, the above discharge scheme can also be adopted, and the discharge rate of each battery unit can be increased as a whole according to the size relationship, or each battery unit can be discharged by adopting the same maximum discharge rate. In addition, when the target battery unit with the thermal runaway risk is located at the end of the battery box, such as the 1# unit or the 8# unit, and the thermal runaway risk level is low, only the target battery unit and the adjacent other battery units may be controlled to be discharged, and the remaining battery units are not discharged.

Fourth implementation mode of thermal runaway control method for battery box

Fig. 9 is a schematic flow chart of a thermal runaway control method for a battery box according to another embodiment of the present invention. In the present embodiment, a battery pack thermal runaway control method is substantially the same as that of the third embodiment shown in fig. 8. The following will explain the main differences of the battery box thermal runaway control method in the four embodiments from the above embodiments with reference to fig. 9.

Alternatively, as shown in fig. 9, in the present embodiment, when the battery cells are controlled to be discharged, the target battery cell may be controlled to be discharged when the risk of the battery cell is low, the target battery cell and other adjacent battery cells may be controlled to be discharged when the risk of the battery cell is medium, and all the battery cells may be controlled to be discharged when the risk of the battery cell is high.

As described above, in some embodiments of the present invention, when the battery box includes at least three battery units, the thermal runaway pre-warning parameter may be divided into at least two continuous threshold ranges, and the threshold ranges correspond to at least two risk levels, respectively, as shown in fig. 7 to 9. Accordingly, when the battery cells are controlled to discharge, the battery cells can be discharged at different discharge rates corresponding to different risk levels. Wherein, the magnitude of the discharge rate is positively correlated with the level of the risk. Through the design, the battery box thermal runaway control method provided by the invention can correspondingly control the battery units to discharge at different discharge rates according to the severity of the thermal runaway risk of the battery units, so that the electric quantity loss of the battery box caused by excessive discharge at a lower risk level is avoided, and the thermal runaway risk is difficult to eliminate due to insufficient discharge at a higher risk level is avoided.

As described above, in some embodiments of the present invention, when the battery box includes at least two battery units, when the thermal runaway risk of any battery unit is detected, the following different methods can be selectively adopted for discharging: all the battery units can be discharged; the target battery cell can be discharged; the target battery cell and other battery cells adjacent thereto may be discharged. Furthermore, when the battery box comprises at least three battery units, the at least three battery units may be divided into at least two battery packs, each battery pack comprising at least two battery units, the at least two battery packs comprising battery units that are not identical. On the basis, when the thermal runaway risk of any battery unit is detected, the following different modes can be selectively adopted for discharging: if the target unit only covers one battery pack, controlling the battery pack to discharge; if the target unit covers at least two battery packs, controlling one battery pack or all battery packs to discharge; all the battery packs can be controlled to be discharged.

As described above, in some embodiments of the present invention, when it is detected that there is a risk of thermal runaway in any battery cell and a discharge scheme is adopted in which the target battery cell and other battery cells are cooperatively discharged, the discharge rate of the other battery cells may be smaller than that of the target battery cell, as shown in fig. 7 to 9. Further, the discharge rates of the other battery cells may be, but are not limited to, 30% to 50% of the discharge rate of the target battery cell.

As described above, based on the detailed descriptions of the second to fourth embodiments of the thermal runaway control method for a battery box according to the present invention, it can be seen that in some embodiments consistent with the design concept of the present invention, if it is detected that any battery cell has a thermal runaway risk when the battery box includes at least two battery cells, the battery cell having the thermal runaway risk and the surrounding battery cells can be selectively discharged according to the risk level.

It should be noted herein that the battery box thermal runaway control methods illustrated in the drawings and described in the present specification are only a few examples of the many types of control methods that can employ the principles of the present invention. It should be clearly understood that the principles of the present invention are by no means limited to any details or any steps of the control method shown in the drawings or described in the present specification.

In summary, the thermal runaway control method for the battery box provided by the invention judges whether the battery unit has a thermal runaway risk or not according to the detection of the thermal runaway early warning parameter of the battery unit, and discharges the electric quantity of the battery unit having the thermal runaway risk. Through the design, the thermal runaway control method for the battery box can reduce the occurrence of thermal runaway and can effectively inhibit the spread of the thermal runaway. Through the design, the battery box thermal runaway control method provided by the invention can effectively utilize the discharged electric quantity and has better economical efficiency and environmental protection.

Based on the above detailed description of several exemplary embodiments of the battery box and the battery box thermal runaway control method according to the present invention, an exemplary embodiment of an electric vehicle according to the present invention will be described below.

In this embodiment, the electric vehicle according to the present invention includes the battery box according to the present invention and described in detail in the above embodiments.

It should be noted herein that the electric vehicles shown in the drawings and described in the present specification are but a few examples of the many types of electric vehicles that can employ the principles of the present invention. It should be clearly understood that the principles of the present invention are in no way limited to any of the details or any of the components of the electric vehicle shown in the drawings or described in this specification.

In summary, the battery box provided by the invention can reduce the occurrence of thermal runaway of the battery box and effectively inhibit the spread of the thermal runaway, so that the electric vehicle provided by the invention has higher safety and reliability.

Based on the above detailed description of several exemplary embodiments of the battery box and the battery box thermal runaway control method according to the present invention, several specific examples to which the battery box or the battery box thermal runaway control method according to the present invention is applied will be described below.

Detailed description of the preferred embodiment

Taking fig. 2 as an example, when it is detected that the voltage change rate of the 5# cell is greater than 10mV/s, the control system determines that the battery box has a risk of thermal runaway and the risk level is the highest level of severity (e.g., high risk). At this time, the control system issues a release switch 310 activation command and issues a first cooling unit 210 and a second cooling unit 220 activation command of the cooling system. Accordingly, all of the bleed-off switches 310 are closed, thereby conducting all of the battery cells 100 with the first cooling unit 210 and the second cooling unit 220 of the cooling system, and discharging at the maximum discharge rate of 10C by controlling the discharge rate.

As shown in fig. 2, when it is detected that the voltage change rate of the 5# cell is greater than 0 and less than 1mV/s, the control system judges that the battery box has a risk of thermal runaway, and the severity is slight (e.g., low risk). At this time, the control system issues an activation command of the bleed switch 310 to bleed the 5# cell and the adjacent 4# cell and 6# cell, and by controlling the discharge rate, the 5# cell is bled at a discharge rate of 5C, and the 4# cell and the 6# cell are bled at a discharge rate of 2C, respectively. The remaining battery cells 100(1# cell to 3# cell, 7# cell to 8# cell) were discharged at a discharge rate of 0.5C, respectively.

As shown in fig. 2, when it is detected that the voltage change rate of the 8# cell is less than 1mV/s, the BMS determines that the battery box has a thermal runaway risk, and the severity is slight, at this time, the control system sends an instruction to activate the bleed switch 310 to bleed the 8# cell and the adjacent 7# cell, and through the control of the discharge rate, the 8# cell is bled at a discharge rate of 5C, the 7# cell is bled at a discharge rate of 2C, and the rest of the battery cells 100 are not bled.

Detailed description of the invention

Taking fig. 5 as an example, when the 8# cell is detected to have thermal runaway, the bypass circuit connected to the 5# cell to the 8# cell, or the bypass circuit connected to the 1# cell to the 4# cell, or the bypass circuit connected to the 3# cell to the 6# cell may be conducted, so that a minimum amount of 50% of the power can be discharged.

As shown in fig. 5, when the 5# cell is detected to have thermal runaway, the bypass circuit connected to the 5# cell to the 8# cell may be conducted, or the bypass circuit connected to the 1# cell to the 4# cell may be conducted, and it is also guaranteed that 50% of the power can be discharged at the minimum.

Exemplary embodiments of a battery box, an electric vehicle, and a battery box thermal runaway control method according to the present invention are described and/or illustrated in detail above. Embodiments of the invention are not limited to the specific embodiments described herein, but rather, components and/or steps of each embodiment may be utilized independently and separately from other components and/or steps described herein. Each component and/or step of one embodiment can also be used in combination with other components and/or steps of other embodiments. When introducing elements/components/etc. described and/or illustrated herein, the articles "a," "an," and "the" are intended to mean that there are one or more of the elements/components/etc. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements/components/etc. other than the listed elements/components/etc. Furthermore, the terms "first" and "second" and the like in the claims and the description are used merely as labels, and are not numerical limitations of their objects.

While the battery box, electric vehicle, and method of thermal runaway control for a battery box according to the present invention have been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.

Claims

1. A battery box, comprising:

a battery cell;

a cooling system to cool the battery cells;

the bypass circuit is connected between the battery unit and the cooling system and is provided with a bleeder switch;

the detection unit is used for detecting a thermal runaway early warning parameter of the battery unit; and

and the control system is connected with the detection unit and the bleeder switch and used for judging whether the battery unit has a thermal runaway risk or not according to the thermal runaway early warning parameter so as to control the bleeder switch when the battery unit has the thermal runaway risk, so that the battery unit discharges electricity and the cooling system is powered by using the discharged electric quantity.

2. The battery box of claim 1, wherein the cooling system comprises a first cooling unit of the type comprising at least one of a liquid cooling device and an air cooling device; and/or, the battery box is used for being arranged on an electric automobile, and the cooling system comprises a second cooling unit which comprises a self-loading cooling device of the electric automobile.

3. The battery box of claim 1, wherein the detection unit comprises a pressure sensor for detecting a pressure change rate of the battery unit, so that the control system can characterize the thermal runaway pre-warning parameter by the pressure change rate; and/or the detection unit comprises a temperature sensor for detecting the temperature change rate of the battery unit so that the control system can represent the thermal runaway early warning parameter according to the temperature change rate.

4. The battery box according to any one of claims 1 to 3, characterized in that:

the battery box comprises at least two battery units and a bypass loop, the at least two battery units are connected in series, and the bypass loop is connected between the cooling system and the two battery units at the head and the tail; and/or

The number of the battery units contained in the battery box is equal to that of the bypass loops, and one bypass loop is connected between each battery unit and the cooling system; and/or

The battery box comprises at least three battery units and at least two branch circuits, each branch circuit is respectively connected between at least two battery units connected in series and the cooling system, and the battery units connected with each branch circuit are not identical.

5. The battery box according to any one of claims 1 to 3, wherein the battery box comprises at least three battery units and at least two bypass circuits, each bypass circuit is respectively connected between at least two battery units connected in series and the cooling system, and the battery units connected by each bypass circuit are not identical; wherein:

the number of said cells connected per said bypass leg is greater than or equal to 1/2 for the total number of said cells; and/or

The number of the battery units connected with each branch circuit is equal.

6. A thermal runaway control method for a battery box is characterized by comprising the following steps:

detecting a thermal runaway early warning parameter of the battery unit;

7. The battery box thermal runaway control method of claim 6, wherein when a thermal runaway risk is judged, the thermal runaway early warning parameter is divided into at least two continuous threshold ranges, and the at least two threshold ranges correspond to at least two risk levels respectively; and when discharging, discharging the battery unit at different discharge rates corresponding to different risk levels, wherein the discharge rate is positively correlated with the risk level.

8. The battery box thermal runaway control method according to claim 7, wherein when the risk of thermal runaway is judged, the threshold range of the thermal runaway early warning parameter is divided into a first threshold range, a second threshold range and a third threshold range from small to large, and the first threshold range, the second threshold range and the third threshold range respectively correspond to a low risk level, a medium risk level and a high risk level; during discharging, the battery unit is discharged at a first discharge rate, a second discharge rate and a third discharge rate corresponding to a low risk level, a medium risk level and a high risk level, wherein the second discharge rate is greater than the first discharge rate and less than the third discharge rate.

9. The battery box thermal runaway control method of claim 6, wherein the battery box contains at least two of the battery cells; and when detecting that any battery unit has a thermal runaway risk, selectively discharging the battery unit with the thermal runaway risk and the surrounding battery units according to the risk grade.

10. An electric vehicle, characterized in that the electric vehicle comprises the battery box according to any one of claims 1 to 5.