Battery box explosion-proof valve, control method thereof, battery assembly and electric vehicle

Abstract

The application relates to a battery box explosion-proof valve and a control method thereof, a battery assembly and an electric vehicle, and an electromagnetic explosion-proof valve which mainly comprises a discharge pipe, a pressure collection pipe, a gas absorption pipe, a plate passing structure, a gas cutoff structure and an electromagnetic regulator; the electromagnetic explosion-proof valve is connected with a BMS, can receive a signal instruction of the battery BMS to control the electromagnetic regulator, the electromagnetic explosion-proof valve is powered by a low-voltage wire harness of the battery assembly, the gas cutoff structure is a pressure threshold opening protection structure, the pressure collection pipe is connected with the BMS, can collect the pressure inside a battery pack and feed back a signal to the BMS, the time interval of the pressure collection pipe for collecting the pressure signal is 0.5s, and the time of each collection action is less than or equal to 50ms; the plate passing structure is fixed on a lower box side plate of a lower box, and the plate passing structure realizes plate passing sealing. The battery box explosion-proof valve has simple structure and high control efficiency, and can effectively solve the industry problem that the gas inside the battery pack cannot be discharged in time in the case of thermal runaway.

Description

Technical Field

[0001] This invention belongs to the field of power battery technology, specifically relating to a battery box explosion-proof valve and its control method, a battery assembly, and an electric vehicle. Background Technology

[0002] As a key component of new energy vehicles, the structural safety performance of power batteries is extremely important. Currently, mainstream battery pack solutions have relatively complex explosion-proof valve structures and suffer from the following two major problems:

[0003] 1. Explosion-proof is passively activated;

[0004] 2. The discharge rate is relatively slow when the battery experiences thermal runaway. Summary of the Invention

[0005] The purpose of this invention is to provide a battery box explosion-proof valve, a battery box explosion-proof valve control method, a battery assembly, and an electric vehicle including the above-mentioned battery assembly, so as to solve the problems of slow passive opening speed of explosion-proof valve and slow discharge speed when battery thermal runaway in the prior art.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] An electromagnetic explosion-proof valve mainly consists of a discharge pipe 301, a pressure acquisition pipe 302, a gas absorption pipe 303, a plate structure 304, a gas cut-off structure 305, and an electromagnetic regulator 306.

[0008] The discharge pipe 301 is connected to the through plate structure 304 by an interference fit with a shaft hole; the pressure acquisition pipe 302 is connected to the through plate structure 304 by a snap-fit; the through plate structure 304 is connected to the gas absorption pipe 303 by an interference fit with a shaft hole; the gas cut-off structure 305 is connected to the gas absorption pipe 303 by an interference fit with a shaft hole; and the electromagnetic regulator 306 is connected to the through plate structure 304 by a snap-fit.

[0009] The electromagnetic explosion-proof valve 3 is connected to the BMS and can receive signal commands from the battery BMS to control the electromagnetic regulator 306; the electromagnetic explosion-proof valve 3 is powered by the low-voltage wiring harness of the battery assembly; the pressure acquisition tube 302 is connected to the BMS and can acquire the pressure inside the battery pack and feed the signal back to the BMS. The pressure acquisition tube 302 acquires the pressure signal at a time interval of 0.5s, and the time for each acquisition action is ≤50ms; the through plate structure 304 is fixed on the lower side plate 2 of the lower housing and achieves through plate sealing.

[0010] Furthermore, the electromagnetic explosion-proof valve 3 contains a coil that can generate an electromagnetic field, thereby controlling the opening size, gas cut-off, and discharge speed of the electromagnetic regulator 306 located in the electromagnetic field.

[0011] Furthermore, the gas cut-off structure 305 is a pressure threshold opening protection structure, which is a passive protection structure that is destroyed when the pressure exceeds the pressure threshold.

[0012] A method for controlling an electromagnetic explosion-proof valve in a battery enclosure includes the following steps:

[0013] A. Pressure acquisition tube 302 acquires the internal pressure of the battery pack and feeds the signal back to the BMS;

[0014] B. The BMS determines whether the battery box needs explosion-proof pressure relief based on the collected pressure. There are four modes: no working mode, normal mode, extreme mode and thermal runaway mode.

[0015] C. Define the highest pressure collected by the BMS as PM, the lowest battery pressure collected by the BMS as PN, the highest battery pressure collected by the BMS as PP, the pressure PW = PM - PN, the safe pressure threshold as PA, and the temperature difference as calculated from the test data every 200 milliseconds.

[0016] In the no-operation mode: PM≤PA / (1.23-lnC*sinC*cotC*expC) and the curvature of PW (with respect to time, in seconds)≤8*(1-lnC*sinC*cotC*expC*exp(sinC)), where C is the pressure compensation coefficient, generally taken as 0.981<C<0.995; the battery management system is inactive, the electromagnetic regulator 306 is not working, and the explosion-proof valve is in a static state;

[0017] Normal mode: PA / (1-lnC*sinC*cotC*expC)≥PM>PA / (1.23-lnC*sinC*cotC*expC) and the curvature of PW (with respect to time, in seconds)≤8*(1-lnC*sinC*cotC*expC*exp(sinC)), where C is the pressure compensation coefficient; the BMS sends a signal command to control the opening degree of the electromagnetic regulator 306 to 50%, and enters the action feedback after working in the mode for 10 minutes;

[0018] Extreme mode: PM > PA / (1-lnC*sinC*cotC*expC) or the curvature of PW (with respect to time, in seconds) > 8*(1-lnC*sinC*cotC*expC*exp(sinC)), where C is the pressure compensation coefficient; the BMS sends a signal command to control the opening degree of the electromagnetic regulator 306 to 100%, and enters the action feedback mode after working in the mode for 10 minutes and enters the action feedback mode after working for 30 minutes;

[0019] Thermal runaway mode: When the BMS receives a battery thermal runaway alarm, the BMS sends a signal command to control the electromagnetic regulator 306 to open to 100%, and the mode continues to operate until the system fails.

[0020] D. Action Feedback: Provides signal feedback on the collected battery pressure.

[0021] Signal judgment: PM≤PA / (1.23-lnC*sinC*cotC*expC) and the curvature of PW change (with respect to time, in seconds)≤8*(1-lnC*sinC*cotC*expC*exp(sinC)), where C is the pressure compensation coefficient, generally taken as 0.981<C<0.995; if the standard is not met, repeat step 3); otherwise, exit control.

[0022] A battery assembly includes a lower housing base plate 1, a lower housing side plate 2, an electromagnetic explosion-proof valve 3, and a battery module 4; the electromagnetic explosion-proof valve 3 is fixed to the lower housing side plate 2; the battery module 4 is fixed to the lower housing base plate 1 by bolts.

[0023] Furthermore, the lower box side panels 2 consist of four pieces, which are respectively erected on the front, rear, left, and right sides of the lower box bottom plate 1 and integrally injection molded with it.

[0024] Furthermore, an opening is made on the rear lower housing side plate 2, through which the electromagnetic explosion-proof valve 3 passes and is fixed to the rear lower housing side plate 2.

[0025] Furthermore, the battery module 4 is fixed to the bottom plate 1 of the lower housing by bolts.

[0026] An electric vehicle including the aforementioned battery assembly.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] The present invention relates to a battery box explosion-proof valve, a battery assembly, and an electric vehicle. The structure is simple and the control is efficient, which can effectively solve the industry problem of untimely discharge of thermal runaway gas inside the battery pack. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0030] Figures 1-2 Structural diagram of the battery housing;

[0031] Figure 3Schematic diagram of the electromagnetic explosion-proof valve;

[0032] In the diagram, 1. Lower housing bottom plate; 2. Lower housing side plate; 3. Electromagnetic explosion-proof valve; 4. Battery module; 301. Drain pipe; 302. Pressure acquisition pipe; 303. Gas absorption pipe; 304. Through plate structure; 305. Gas cut-off structure; 306. Electromagnetic regulator. Detailed Implementation

[0033] The present invention will be further described below with reference to embodiments:

[0034] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0035] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0036] like Figures 1-2 As shown, the present invention provides a battery assembly, including a lower housing base plate 1, lower housing side plates 2, an electromagnetic explosion-proof valve 3, and a battery module 4. The lower housing side plates 2 consist of four pieces, which are respectively erected on the front, rear, left, and right sides of the lower housing base plate 1 and integrally injection molded with it.

[0037] The rear lower housing side panel 2 has an opening, through which the electromagnetic explosion-proof valve 3 passes and is fixed to the rear lower housing side panel 2.

[0038] The battery module 4 is fixed to the bottom plate 1 of the lower housing by bolts.

[0039] like Figure 3 As shown, the electromagnetic explosion-proof valve 3 mainly consists of a discharge pipe 301, a pressure acquisition pipe 302, a gas absorption pipe 303, a plate structure 304, a gas cut-off structure 305, and an electromagnetic regulator 306.

[0040] The discharge pipe 301 is connected to the through plate structure 304 by an interference fit with a shaft hole; the pressure acquisition pipe 302 is connected to the through plate structure 304 by a snap-fit; the through plate structure 304 is connected to the gas absorption pipe 303 by an interference fit with a shaft hole; the gas cut-off structure 305 is connected to the gas absorption pipe 303 by an interference fit with a shaft hole; and the electromagnetic regulator 306 is connected to the through plate structure 304 by a snap-fit.

[0041] The electromagnetic explosion-proof valve 3 is connected to the battery management system (BMS) and can receive signal commands from the BMS to control the electromagnetic regulator 306.

[0042] The electromagnetic explosion-proof valve 3 contains a coil that generates an electromagnetic field, controlling the electromagnetic regulator 306 located within this field. This controls the opening size of the electromagnetic regulator 306, thereby controlling the gas shut-off and emission speed. The opening size of the electromagnetic regulator 306 can be controlled by various structures, including but not limited to valves and springs. Specifically, the coil is located inside 304, around 306.

[0043] The electromagnetic explosion-proof valve 3 is powered by the low-voltage wiring harness of the battery assembly. The low-voltage wiring harness is connected to the pressure acquisition tube 302, and the wiring harness is plugged into the pressure sensor.

[0044] The gas cut-off structure 305 is a pressure threshold opening protection structure, which is a passive protection structure. It is destroyed when the pressure exceeds the pressure threshold. The specific material form includes, but is not limited to, diaphragms, rubber, etc.

[0045] The pressure acquisition tube 302 is connected to the BMS and can acquire the pressure inside the battery pack and feed the signal back to the BMS. The pressure acquisition tube 302 acquires the pressure signal at a time interval of 0.5s, and the time for each acquisition action is ≤50ms.

[0046] The through-plate structure 304 is fixed to the lower box side plate 2 of the lower box, and the through-plate structure 304 achieves through-plate sealing. The through-plate structure 304 and the lower box side plate 2 are fixed by means including but not limited to snap-fit, adhesive, and external edge welding.

[0047] The dimensions of the electromagnetic explosion-proof valve 3 are determined in the following manner:

[0048] The limit dimensions of the explosion-proof valve are determined based on the maximum safety factor ZQ for battery thermal runaway pressure relief and the battery cavity expansion force coefficient BH: Limit dimension volume Where CC is the battery safety protection factor, which is generally taken as 0.56-0.72; A is the explosion-proof valve compensation parameter, which is generally taken as 8°>A>0°;

[0049] The dimensions of phase change battery thermal management structure 1 are determined based on V:

[0050] Define the total area of ​​the bend as: D=S / (CF*E) / (CF*E)*0.85*cos(lnA)*cos(exp(A), where CF is the design height limit dimension, E is the safety dimension factor, which is generally taken as 1.23-1.93; n is the number of liquid cooling plates;

[0051] Define the overall length:

[0052]

[0053] All parameters need to be corrected and fed back based on CAE and CFD simulation results.

[0054] The present invention also provides an electric vehicle including the aforementioned battery assembly.

[0055] This invention also provides a method for controlling an explosion-proof valve in a battery enclosure, including signal reception, mode determination, action execution, and action feedback. Specifically, it includes the following steps:

[0056] 1. Pressure acquisition tube 302 acquires the internal pressure of the battery pack and feeds the signal back to the BMS;

[0057] 2. The BMS determines whether the battery box needs explosion-proof pressure relief based on the collected pressure. There are four modes: no working mode, normal mode, extreme mode and thermal runaway mode.

[0058] 3. Define the highest battery pressure collected by the BMS as PM, the lowest battery pressure collected by the BMS as PN, the pressure difference PW = PM - PN, the safe pressure threshold as PA, and the temperature difference as calculated from the test data every 200 milliseconds.

[0059] In the no-operation mode: PM≤PA / (1.23-lnC*sinC*cotC*expC) and the curvature of PW (with respect to time, in seconds)≤8*(1-lnC*sinC*cotC*expC*exp(sinC)), where C is the pressure compensation coefficient, generally taken as 0.981<C<0.995; the battery management system is inactive, the electromagnetic regulator 306 is not working, and the explosion-proof valve is in a static state;

[0060] Normal mode: PA / (1-lnC*sinC*cotC*expC)≥PM>PA / (1.23-lnC*sinC*cotC*expC) and the curvature of PW (with respect to time, in seconds)≤8*(1-lnC*sinC*cotC*expC*exp(sinC)), where C is the pressure compensation coefficient; the BMS sends a signal command to control the opening degree of electromagnetic regulator 306 to 50%. The mode enters motion feedback after 10 minutes of operation.

[0061] Extreme mode: PM > PA / (1-lnC*sinC*cotC*expC) or the curvature of PW (with respect to time, in seconds) > 8*(1-lnC*sinC*cotC*expC*exp(sinC)), where C is the pressure compensation coefficient; the BMS sends a signal command to control the opening degree of electromagnetic regulator 306 to 100%. The system enters motion feedback mode after 10 minutes of operation and motion feedback mode after 30 minutes of operation.

[0062] Thermal runaway mode: Upon receiving a battery thermal runaway alarm, the BMS issues a signal command to control the electromagnetic regulator 306 to open to 100%. This mode operates until system failure.

[0063] 4. Action Feedback: Provides signal feedback on the collected battery pressure.

[0064] Signal judgment: PM≤PA / (1.23-lnC*sinC*cotC*expC) and the curvature of PW change (with respect to time, in seconds)≤8*(1-lnC*sinC*cotC*expC*exp(sinC)), where C is the pressure compensation coefficient, generally taken as 0.981<C<0.995; if the standard is not met, repeat step 3); otherwise, exit control.

[0065] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. An electromagnetic explosion-proof valve, characterized in that: It mainly consists of a discharge pipe (301), a pressure acquisition pipe (302), a gas absorption pipe (303), a plate structure (304), a gas cut-off structure (305), and an electromagnetic regulator (306); The discharge pipe (301) and the through plate structure (304) are connected by an interference fit with a shaft hole; the pressure acquisition pipe (302) and the through plate structure (304) are connected by a snap-fit; the through plate structure (304) and the gas absorption pipe (303) are connected by an interference fit with a shaft hole; the gas cut-off structure (305) and the gas absorption pipe (303) are connected by an interference fit with a shaft hole; the electromagnetic regulator (306) and the through plate structure (304) are connected by a snap-fit. The electromagnetic explosion-proof valve (3) is connected to the BMS and can receive signal commands from the battery BMS to control the electromagnetic regulator (306); the electromagnetic explosion-proof valve (3) is powered by the low-voltage wiring harness of the battery assembly; the pressure acquisition tube (302) is connected to the BMS and can acquire the pressure inside the battery pack and feed the signal back to the BMS. The pressure acquisition tube (302) acquires the pressure signal at intervals of 0.5s, and the acquisition action time is ≤50ms; the through plate structure (304) is fixed on the lower side plate (2) of the lower box and the through plate structure (304) achieves through plate sealing; The electromagnetic explosion-proof valve (3) contains a coil that can form an electromagnetic field to control the opening size, gas cut-off, and discharge speed of the electromagnetic regulator (306) located in the electromagnetic field. The gas cut-off structure (305) is a pressure threshold opening protection structure, which is a passive protection structure. It will be destroyed if the pressure exceeds the pressure threshold. The control method for the electromagnetic explosion-proof valve of the battery box includes the following steps: A. The pressure acquisition tube (302) acquires the pressure inside the battery pack and feeds the signal back to the BMS; B. The BMS determines whether the battery box needs explosion-proof pressure relief based on the collected pressure. There are four modes: no working mode, normal mode, extreme mode and thermal runaway mode. C. Define the highest battery pressure collected by the BMS as PM, the lowest battery pressure collected by the BMS as PN, the pressure PW = PM - PN, the safe pressure threshold as PA, and the temperature difference as calculated from the test data every 200 milliseconds. In the no-operation mode: PM≤PA / (1.23-lnC* sinC*cotC*expC) and the curvature of PW change≤8*(1-lnC* sinC*cotC*expC*exp(sinC)); the battery management system is inactive, the electromagnetic regulator 306 is not working, and the explosion-proof valve is in a static state. Normal mode: PA / (1-lnC* sinC*cotC*expC)≥PM>PA / (1.23-lnC* sinC*cotC*expC) and the curvature of PW change ≤8*(1- lnC* sinC*cotC*expC*exp(sinC)); BMS sends a signal command to control the opening degree of electromagnetic regulator 306 to 50%, and enters action feedback after working in mode for 10 minutes; Extreme mode: PM > PA / (1-lnC* sinC*cotC*expC) or the curvature of PW change > 8*(1- lnC* sinC*cotC*expC*exp(sinC)); BMS sends a signal command to control the opening degree of electromagnetic regulator (306) to 100%. After working in mode for 10 minutes, it enters motion feedback mode. After working in mode for 30 minutes, it enters motion feedback mode. Thermal runaway mode: When the BMS receives a battery thermal runaway alarm, the BMS sends a signal command to control the electromagnetic regulator (306) to open to 100%, and the mode works until the system fails. D. Action Feedback: Provides signal feedback on the collected battery pressure. Signal judgment: PM≤PA / (1.23-lnC*sinC*cotC*expC) and the curvature of PW change≤8*(1-lnC*sinC*cotC*expC*exp(sinC)); if the criteria are not met, repeat step C; otherwise, exit control. Where C is the pressure compensation coefficient, taken as 0.981 < C < 0.995; the curvature of PW change with respect to time, in seconds.

2. A battery assembly, characterized in that: The device includes an electromagnetic explosion-proof valve (3) as described in claim 1, and also includes a lower housing bottom plate (1), a lower housing side plate (2), and a battery module (4); the electromagnetic explosion-proof valve (3) is fixed to the lower housing side plate (2); the battery module (4) is fixed to the lower housing bottom plate (1) by bolts.

3. A battery assembly according to claim 2, characterized in that: The lower box side panels (2) consist of 4 pieces, which are respectively placed in front, back, left and right sides of the lower box bottom plate (1) and are integrally formed with it by injection molding.

4. A battery assembly according to claim 2, characterized in that: An opening is made on the rear lower box side panel (2), and the electromagnetic explosion-proof valve (3) passes through the opening and is fixed to the rear lower box side panel (2).

5. An electric vehicle, characterized in that: Includes a battery assembly as described in claim 2.

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