Battery cell thermal runaway detection system and method of lithium battery module

Abstract

The invention discloses a battery cell thermal runaway detection system and method for a lithium battery module, and belongs to the field of power battery thermal runaway prediction.The system comprises the lithium battery module, a plurality of battery cells are distributed in the lithium battery module in rows and columns, and a control circuit is arranged at a ventilation channel between every two adjacent battery cells; the U-shaped sliding rail comprises a first section of linear part and a second section of linear part which are connected through an arc part, a first movable fan and a second movable fan are arranged on the U-shaped sliding rail, and the first movable fan and the second movable fan horizontally move on the first section of linear part or the second section of linear part at the same time; each control circuit comprises a proximity switch K1, temperature sensors W1-Wn, a gas sensor W, a triode Q1, a triode Q2, resistors R1-R5, a light emitting diode D1, a photodiode D2, a selective switch K2 and a capacitor C1. According to the invention, rapid detection and accurate positioning of the thermal runaway cell can be realized.

Description

Technical Field

[0001] The present invention belongs to the field of thermal runaway prediction of power batteries, and specifically relates to a battery cell thermal runaway detection system and method for a lithium battery module. Background Art

[0002] With the increase in the number of new energy vehicles, a certain number of new energy vehicle spontaneous combustion incidents occur every year. Many new energy vehicle fires are related to power batteries. Power battery thermal runaway refers to the overheating, fire, and explosion phenomenon caused by a sharp change in the battery's self-temperature rise rate due to the chain reaction of heat release from the single battery.

[0003] At present, the method of leaking gas detection is recognized as an effective method for pre-judging thermal runaway. The steps for pre-judging thermal runaway include: first, waiting for a small amount of leaked gas from the battery that is about to thermally runaway to diffuse freely to the location of the gas sensor; then, relying on the response of the gas sensor to determine whether thermal runaway will occur. However, this detection method that relies on the free diffusion of gas is difficult to quickly locate the location of the thermal runaway battery, and the diffusion of thermal runaway gas has a certain delay. Summary of the invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a system and method for detecting thermal runaway of a lithium battery module. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0005] In a first aspect, an embodiment of the present invention provides a battery cell thermal runaway detection system for a lithium battery module, the system comprising:

[0006] A lithium battery module, wherein a plurality of battery cells are arranged in rows and columns, and a control circuit is arranged at each ventilation channel between adjacent battery cells; a U-shaped slide rail, wherein the U-shaped slide rail comprises a first straight line portion and a second straight line portion connected by an arc portion, wherein the first straight line portion is arranged on one side of all battery cells arranged in the columns, and the second straight line portion is arranged on one side of all battery cells arranged in the rows, wherein the battery cells in the first column are close to the second straight line portion, and the battery cells in the first row are close to the first straight line portion, and wherein a first movable fan and a second movable fan are arranged on the U-shaped slide rail, wherein the first movable fan and the second movable fan move horizontally on the first straight line portion or the second straight line portion at the same time; wherein,

[0007] Each control circuit includes a proximity switch K1, a temperature sensor W1 to a temperature sensor Wn, a gas sensor W, a transistor Q1, a transistor Q2, resistors R1 to R5, a light emitting diode D1, a photodiode D2, a selection switch K2, and a capacitor C1; wherein one end of the proximity switch K1, one end of the resistor R3, one end of the resistor R4, and one end of the resistor R5 are all connected to a power supply, for example, the voltage of the power supply is 5V, the other end of the proximity switch K1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to one end of the resistor R2 and one end of the capacitor C1, the other end of the capacitor C1, the emitter of the transistor Q1, and the emitter of the temperature sensor W1 to the temperature sensor Wn. One end and the emitter of the transistor Q2 are grounded, the other end of the resistor R2 is connected to the base of the transistor Q1, the collector of the transistor Q1 is connected to the cathode of the light-emitting diode D1, the anode of the light-emitting diode D1 is connected to the other end of the resistor R3, the other end of the resistor R4 is connected to the cathode of the photodiode D2, the anode of the photodiode D2 is connected to the base of the transistor Q2 and one end of the selection switch K2, the other end of the selection switch K2 is connected to the other end of any temperature sensor selected from the temperature sensor W1 to the temperature sensor Wn, the other end of the resistor R5 is connected to one end of the gas sensor W, and the other end of the gas sensor W is connected to the collector of the transistor Q2.

[0008] In a second aspect, an embodiment of the present invention provides a method for detecting thermal runaway of a cell of a lithium battery module, which is applied to a thermal runaway detection system for a cell of a lithium battery module as described in any one of the first aspects, and the corresponding detection method includes:

[0009] When the first movable fan and the second movable fan are respectively moved to the ventilation channel, the corresponding proximity switch K1 is triggered, and the proximity switch K1 is closed. At this time, the transistor Q1 is not turned on, and the capacitor C1 starts to charge;

[0010] As the voltage of capacitor C1 gradually increases, transistor Q1 is turned on, and light-emitting diode D1 is turned on; when the light of light-emitting diode D1 irradiates photodiode D2, current flows through photodiode D2, causing selection switch K2 to start working, and temperature sensors W1 to Wn are connected to the control circuit in sequence;

[0011] When the resistance of any temperature sensor among the temperature sensors W1 to Wn increases, the transistor Q2 is turned on and the gas sensor W starts to work.

[0012] When the first movable fan and the second movable fan leave the ventilation channel respectively, the corresponding proximity switch K1 is opened, the capacitor C1 starts to discharge, and current still flows through the resistor R2, and the control circuit continues to work for a period of time; when the voltage of the capacitor C1 drops to the point where the transistor Q1 is cut off, the temperature sensors W1 to Wn and the gas sensor W are all turned off, and the control circuit stops working.

[0013] In one embodiment of the present invention, the detection method further comprises:

[0014] The process of performing thermal runaway detection and positioning on the cells distributed in a row on the first straight line portion includes:

[0015] Column initial state: the first movable fan and the second movable fan are respectively located at the ventilation channels on both sides of the last column of cells, entering the column detection preparation state;

[0016] Column detection preparation state: when the first movable fan and the second movable fan move to the corresponding ventilation channel, the proximity switch at the corresponding ventilation channel is triggered, and they stay at the corresponding ventilation channel for a period of time, respectively, and after the abnormal thermal runaway gas diffused from other places in the early stage is blown away and the heat is dissipated, the control circuit set at the corresponding ventilation channel is turned on, and the column-by-column detection state or the column range detection state is entered;

[0017] Column-by-column detection state: the first movable fan and the second movable fan respectively move forward from both sides of the last column of battery cells to detect the ventilation channels on both sides of each column of battery cells one by one; wherein, in a certain column detection positioning: if the temperature sensor in the control circuit detects abnormal temperature, the abnormal row range where the thermal runaway battery cell is located is determined and the gas sensor in the control circuit is turned on; if the gas sensor detects abnormal gas, the column where the thermal runaway battery cell is located is located, and at the same time, the first movable fan and the second movable fan enter the row detection preparation state; if the gas sensor does not detect abnormal gas, the first movable fan and the second movable fan enter the row initial state;

[0018] Column range detection state: after the first movable fan and the second movable fan pass through the arc part and reach the first straight line part, adjust the distance between the first movable fan and the second movable fan to be equal to the distance between two adjacent proximity switches, and move the first movable fan and the second movable fan to the corresponding ventilation channel according to the abnormal column range, so that the first movable fan and the second movable fan can detect within the abnormal column range; if the gas sensors of the first movable fan and the second movable fan detect abnormal gas within the abnormal column range, determine the column where the thermal runaway cell is located, and determine the position of the thermal runaway cell according to the row and column where the thermal runaway cell is located; if the gas sensors of the first movable fan and the second movable fan do not detect abnormal gas within the abnormal column range, the first movable fan and the second movable fan move to the column initial state;

[0019] The process of performing thermal runaway detection and positioning on the row-distributed cells on the second straight line portion includes:

[0020] Row initial state: the first movable fan and the second movable fan are respectively located at the ventilation channels on both sides of the last row of cells, entering the row detection preparation state;

[0021] Row detection preparation state: when the first movable fan and the second movable fan move to the corresponding ventilation channel, the proximity switch at the corresponding ventilation channel is triggered, and they stay at the corresponding ventilation channel for a period of time, respectively, and after the abnormal thermal runaway gas diffused from other places in the early stage is blown away and the heat is dissipated, the control circuit set at the corresponding ventilation channel is turned on, and the row-by-row detection state or the row range detection state is entered;

[0022] Row-by-row detection state: the first movable fan and the second movable fan respectively move forward from both sides of the last row of battery cells to detect the ventilation channels on both sides of each row of battery cells one by one; wherein, in the detection and positioning of a certain row: if the temperature sensor in the control circuit detects abnormal temperature, the abnormal column range where the thermal runaway battery cell is located is determined and the gas sensor in the control circuit is turned on; if the gas sensor detects abnormal gas, the row where the thermal runaway battery cell is located is located, and at the same time, the first movable fan and the second movable fan enter the column detection preparation state; if the gas sensor does not detect abnormal gas, the first movable fan and the second movable fan enter the column initial state;

[0023] Row range detection state: after the first movable fan and the second movable fan pass through the arc part and reach the second straight line part, adjust the distance between the first movable fan and the second movable fan to be equal to the distance between two adjacent proximity switches, and move the first movable fan and the second movable fan to the corresponding ventilation channel according to the abnormal row range, so that the first movable fan and the second movable fan can be detected within the abnormal row range; if the gas sensors of the first movable fan and the second movable fan detect abnormal gas within the abnormal column range, determine the row where the thermal runaway cell is located, and determine the position of the thermal runaway cell according to the determined row and column where the thermal runaway cell is located; if the gas sensors of the first movable fan and the second movable fan do not detect abnormal gas within the abnormal column range, the first movable fan and the second movable fan move to the row initial state.

[0024] Beneficial effects of the present invention:

[0025] The battery cell thermal runaway detection system of the lithium battery module proposed in the present invention can realize rapid detection and precise positioning of thermal runaway batteries through the cooperation of the control circuit and two movable fans. Specifically: after the two movable fans move to the corresponding ventilation channels, the temperature sensor in the control circuit first detects whether thermal runaway occurs. When the temperature sensor detects an abnormality, the gas sensor in the control circuit further judges, and the two movable fans can locate the column where the thermal runaway battery cell is located on the first straight line portion, and can locate the row where the thermal runaway battery cell is located on the second straight line portion. Then, the position of the thermal runaway battery cell can be determined according to the located column and row of the thermal runaway battery cell, thereby realizing rapid detection and precise positioning of the thermal runaway battery cell. The present invention can reduce power consumption because the temperature sensor in the control circuit is turned on only after the two movable fans trigger the proximity switch, and the gas sensor is turned on only after the temperature sensor detects an abnormality, which further reduces power consumption, thereby effectively saving the power supply time of the temperature sensor and the gas sensor, and extending the service life of the temperature sensor and the gas sensor; the control circuit can realize delayed opening of the control circuit through capacitors and resistors; the two movable fans continue to rotate during the detection process, so that the influence of heat and interfering gases transmitted from other places on the detection is reduced; at the same time, the two movable fans can simultaneously detect a row or a column of battery cells, thereby improving the detection speed.

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of a battery cell thermal runaway detection system for a lithium battery module provided by an embodiment of the present invention;

[0028] Figure 2The embodiment of the present invention provides Figure 1 A partial enlarged view of the arc portion of the U-shaped slide rail;

[0029] Figure 3 A schematic diagram of the circuit structure of a control circuit provided in an embodiment of the present invention;

[0030] Figure 4 The embodiment of the present invention provides Figure 1 A partial enlarged view of the middle U-shaped slide rail;

[0031] Figure 5 The embodiment of the present invention provides Figure 1 Structural diagram of the proximity switch and the U-shaped slide rail position;

[0032] Figure 6 A schematic diagram of the structure of a movable fan provided by an embodiment of the present invention;

[0033] Figure 7 A schematic diagram of the structure of the movable windshield and the position of the temperature sensor provided in an embodiment of the present invention;

[0034] Figure 8 A schematic diagram of the structure of a movable windshield provided in an embodiment of the present invention;

[0035] Fig. 9 A schematic diagram of the structure of a selection switch provided in an embodiment of the present invention;

[0036] Fig.10 A schematic diagram of the air outlet position and structure provided in an embodiment of the present invention;

[0037] Fig.11 A schematic diagram of the gas flow between battery cells distributed in rows and columns provided in an embodiment of the present invention.

[0038] Description of reference numerals:

[0039] 1-U-shaped slide rail; 2-first movable fan; 3-second movable fan; 4-selection switch; 5-air outlet; 6-movable wind shield; 7-battery cell; 8-pulley; 9-first micro reducer; 10-first micro motor; 11-fan; 12-proximity switch; 13-temperature sensor; 14-gas sensor; 15-rotating part; 16-second micro reducer; 17-second micro motor; 18-base; 19-wind shield B side; 20-wind shield A side; 21-central axis. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0041] First, see Figure 1 , Figure 2 , Figure 3 The embodiment of the present invention provides a battery cell thermal runaway detection system for a lithium battery module, the system comprising:

[0042] A lithium battery module, wherein a plurality of battery cells 7 are arranged in rows and columns in the lithium battery module, and a control circuit is arranged at each ventilation passage between adjacent battery cells 7; a U-shaped slide rail 1, wherein the U-shaped slide rail 1 comprises a first straight line portion and a second straight line portion connected by an arc portion, wherein the first straight line portion is arranged on one side of all battery cells 7 arranged in the columns, and the second straight line portion is arranged on one side of all battery cells 7 arranged in the rows, wherein the battery cells 7 in the first column are close to the second straight line portion, and the battery cells 7 in the first row are close to the first straight line portion, and a first movable fan 2 and a second movable fan 3 are arranged on the U-shaped slide rail 1, and the first movable fan 2 and the second movable fan 3 move horizontally on the first straight line portion or the second straight line portion at the same time; wherein,

[0043] Each control circuit includes a proximity switch K1, a temperature sensor W1 to a temperature sensor Wn, a gas sensor W, a transistor Q1, a transistor Q2, resistors R1 to R5, a light emitting diode D1, a photodiode D2, a selection switch K2, and a capacitor C1; wherein one end of the proximity switch K1, one end of the resistor R3, one end of the resistor R4, and one end of the resistor R5 are all connected to a power supply, the other end of the proximity switch K1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to one end of the resistor R2 and one end of the capacitor C1, the other end of the capacitor C1, the emitter of the transistor Q1, one end of the temperature sensor W1 to the temperature sensor Wn, the transistor The emitter of transistor Q2 is grounded, the other end of resistor R2 is connected to the base of transistor Q1, the collector of transistor Q1 is connected to the cathode of light-emitting diode D1, the anode of light-emitting diode D1 is connected to the other end of resistor R3, the other end of resistor R4 is connected to the cathode of photodiode D2, the anode of photodiode D2 is connected to the base of transistor Q2 and one end of selection switch K2, the other end of selection switch K2 is connected to the other end of any temperature sensor among temperature sensor W1 to temperature sensor Wn, the other end of resistor R5 is connected to one end of gas sensor W, and the other end of gas sensor W is connected to the collector of transistor Q2.

[0044] The control circuit provided at each ventilation channel of the embodiment of the present invention can control the corresponding temperature sensor and gas sensor to open through the light-emitting diode D1 and the photodiode D2. The control circuit is composed of a proximity switch K1, multiple temperature sensors (W1~Wn), a gas sensor W1, two transistors (Q1, Q2), 5 fixed resistors (R1, R2, R3, R4, R5), a light-emitting diode D1, a photodiode D2, a selection switch K2, and a capacitor C1. Among them, the proximity switch K1 is installed on the side wall of the lithium battery module opposite to the corresponding ventilation channel, the gas sensor W is installed at the end of the corresponding ventilation channel, the transistor Q1, the transistor Q2, the resistor R1~resistor R5, the light-emitting diode D1, the photodiode D2, the selection switch K2, and the capacitor C1 are integrated and installed on the lower surface of the lithium battery module at the corresponding ventilation channel, and the temperature sensor W1~temperature sensor Wn are installed on the surface of the corresponding battery cell 7. Two temperature sensors are installed on the surface of each battery cell 7, one temperature sensor is used in the control circuit set at the corresponding ventilation channel of the row distribution, and the other temperature sensor is used in the control circuit set at the corresponding ventilation channel of the column distribution. The temperature sensor on the battery cell 7 distributed in a row and the temperature sensor on the battery cell 7 distributed in a column respectively constitute the temperature sensor W1 to the temperature sensor Wn in their respective control circuits. The detection process of the battery cells 7 distributed in rows: select the temperature sensor corresponding to a certain battery cell 7 in the row from the temperature sensors W1 to the temperature sensors Wn corresponding to each row through the selection switch K2 to connect to the control circuit; similarly, the detection process of the battery cells 7 distributed in columns: select the temperature sensor corresponding to a certain battery cell 7 in the column from the temperature sensors W1 to the temperature sensors Wn corresponding to each column through the selection switch K2 to connect to the control circuit. Among them, n represents the number of cells 7 distributed in rows or columns, and the value of n is determined according to the actual situation. The subscript n represents the temperature sensor set on the nth cell 7 distributed in rows or columns. The figure shows the case of n=4, which means that the number of cells 7 distributed in rows or columns is 4, and the temperature sensors corresponding to the rows or columns of these four cells 7 are respectively recorded as W1~W4. It can be seen that for the lithium battery module, the cells 7 distributed in rows and columns are respectively designed with corresponding control circuits, so that the cell row and column channels can be detected simultaneously during the detection process. Figure 1 Mark 4 is the selection switch K2.

[0045] The U-shaped rail 1 of the embodiment of the present invention is fixedly installed on the side wall of the lithium battery module, and can be fixed by screws or embedded in the side wall of the battery module. The U-shaped rail 1 includes three parts: a first straight line part, an arc part, and a second straight line part. The first straight line part and the second straight line part are connected together by the arc part. A plurality of small holes are arranged at intervals on the first straight line part and the second straight line part. Figure 4As shown, each small hole is opposite to a ventilation channel, so that when the first movable fan 2 and the second movable fan 3 move to the small hole, the corresponding proximity switch is triggered. Figure 5 As shown, the proximity switch is located behind the small holes of the first straight line portion and the second straight line portion. When the pulley 8 on the first movable fan 2 and the second movable fan 3 approaches and blocks the small holes, the corresponding temperature sensor and gas sensor can be turned on and off with delay through the proximity switch. Figure 5 The mark 12 is the proximity switch K1.

[0046] In the embodiment of the present invention, the first movable fan 2 and the second movable fan 3 have the same structure; Figure 6 As shown, it includes a first micro motor 10, a first micro reducer 9, a fan 11 and a pulley 8; wherein the fan 11 is mounted on the first micro motor 10, the first micro motor 10 is connected to the first micro reducer 9, and the first micro reducer 9 drives the pulley 8 to move horizontally on the U-shaped slide rail 1. Figure 6 The structure shown can control the two movable fans to move horizontally on the U-shaped slide rail 1 through the pulley 8.

[0047] In the embodiment of the present invention, two temperature sensors are arranged on each battery cell 7. Figure 7 As shown, the resistance value of the side of each battery cell 7 close to the pole ear increases with the increase of temperature. Figure 7 The reference numeral 13 is a temperature sensor.

[0048] In the embodiment of the present invention, each battery cell 7 is provided with a movable wind shield 6, which can close the ventilation channel perpendicular to the wind direction according to the wind direction; the movable wind shield 6 is as shown in FIG. Figure 8 As shown, it includes a windshield A surface 20, a central axis 21 and a windshield B surface 19; wherein the windshield B surface 19 is fixedly installed on the surface of the corresponding battery cell 7; the windshield A surface 20 rotates around the central axis 21 with the flow of gas to close the ventilation channel perpendicular to the wind direction. When the windshield B surface 19 is fixedly installed on the surface of the battery cell 7, the fixing method is screw connection, etc., and the windshield A surface 20 can rotate around the central axis 21 with the flow of gas. It can be seen that using Figure 8 In the structure shown, during the detection process, as the movable fan moves, the movable wind shield 6 is controlled to close the ventilation channel perpendicular to the wind direction, so that the thermal runaway gas can be quickly transmitted to the gas sensor, so that the gas sensor can detect the thermal runaway gas signal caused by the thermal runaway more quickly, thereby quickly locating the position of the thermal runaway battery cell 7.

[0049] In the embodiment of the present invention, the switch K2 is selected in each control circuit as follows: Fig. 9As shown, they all include a rotating component 15, a second micro motor 17, a second micro reducer 16 and a base 18; wherein the base 18 is fixedly installed on the lower surface of the lithium battery module at the ventilation channel corresponding to the control circuit, and the second micro motor 17 is installed on the base 18, and the second micro motor 17 is connected to the second micro reducer 16, and the second micro reducer 16 drives the rotating component 15 to rotate, so that the rotating component 15 can select to connect to any temperature sensor among the temperature sensors W1 to Wn; wherein the transistor Q1, the transistor Q2, the resistor R1 to the resistor R5, the light emitting diode D1, the photodiode D2, and the capacitor C1 are integrated and installed in the base 18. It can be seen that the embodiment of the present invention utilizes Fig. 9 The structure shown can select corresponding temperature sensors from the battery cells 7 distributed in rows or columns to be connected to the control circuit, so that more comprehensive detection of the battery cells 7 can be achieved during the detection process. Figure 3 M in the figure is the second micro motor 17 .

[0050] In the embodiment of the present invention, an air outlet 5 is arranged around the gas sensor W installed at the end of each ventilation channel. Fig.10 As shown; wherein, when the first movable fan 2 and the second movable fan 3 pass through the corresponding ventilation channel, the wind direction is facing the gas sensor W and flows out through the surrounding air outlet 5 around the gas sensor W. Fig.10 The reference numeral 14 is a gas sensor W.

[0051] Fig.11 The gas flow between the cells 7 arranged in rows and columns is shown. For such gas flow, the system provided in the embodiment of the present invention can fully detect it. Fig.11 The left side of the figure illustrates the gas flow of the column-distributed cells 7 in each ventilation channel, and the right side illustrates the gas flow of the row-distributed cells 7 in each ventilation channel.

[0052] To summarize, the battery cell thermal runaway detection system for the lithium battery module provided in the embodiment of the present invention can achieve rapid detection and precise positioning of thermal runaway batteries through the coordinated work of the control circuit and two movable fans. Specifically: after the two movable fans move to the corresponding ventilation channels, the temperature sensor in the control circuit first detects whether thermal runaway occurs. When the temperature sensor detects an abnormality, the gas sensor in the control circuit further judges, and the two movable fans can locate the column where the thermal runaway battery cell is located on the first straight line portion, and can locate the row where the thermal runaway battery cell is located on the second straight line portion, and then the position of the thermal runaway battery cell can be determined according to the located column and row of the thermal runaway battery cell, thereby achieving rapid detection and precise positioning of the thermal runaway battery cell. The embodiment of the present invention can reduce power consumption because the temperature sensor body in the control circuit is turned on only after the two movable fans trigger the proximity switch, and the gas sensor is turned on only after the temperature sensor detects an abnormality, further reducing power consumption, thereby effectively saving the power supply time of the temperature sensor and the gas sensor, and extending the service life of the temperature sensor and the gas sensor; the control circuit can delay the opening of the control circuit through capacitors and resistors; the two movable fans continue to rotate during the detection process, so that the influence of heat and interfering gases transmitted from other places on the detection is reduced; at the same time, the two movable fans can simultaneously detect a row or a column of battery cells, thereby improving the detection speed.

[0053] The detection system proposed in the present invention can avoid the problem that when the temperature sensor threshold value is too high, thermal runaway has already occurred when the temperature sensor detects a signal, and when the temperature sensor threshold value is too low, the detection signal is disturbed.

[0054] In a second aspect, an embodiment of the present invention provides a method for detecting thermal runaway of a cell of a lithium battery module, which is applied to the thermal runaway detection system for a cell of a lithium battery module proposed in the first aspect, and the corresponding detection method includes:

[0055] When the first movable fan 2 and the second movable fan 3 are respectively moved to the ventilation channel, the corresponding proximity switch K1 is triggered, and the proximity switch K1 is closed. At this time, the transistor Q1 is not turned on, and the capacitor C1 starts to charge;

[0056] As the voltage of capacitor C1 gradually increases, transistor Q1 is turned on, and light-emitting diode D1 is turned on; when the light of light-emitting diode D1 irradiates photodiode D2, current flows through photodiode D2, causing selection switch K2 to start working, and temperature sensors W1 to Wn are connected to the control circuit in sequence;

[0057] When the resistance of any temperature sensor among the temperature sensors W1 to Wn increases, the transistor Q2 is turned on and the gas sensor W starts to work.

[0058] When the first movable fan 2 and the second movable fan 3 leave the ventilation passage respectively, the corresponding proximity switch K1 is turned on, the capacitor C1 starts to discharge, and the current still flows through the resistor R2, and the control circuit continues to work for a period of time; when the voltage of the capacitor C1 drops to the point where the transistor Q1 is turned off, the temperature sensors W1 to Wn and the gas sensor W are all turned off, and the control circuit stops working. More specifically:

[0059] As the first movable fan 2 and the second movable fan 3 move to the ventilation channel, the corresponding proximity switch K1 is triggered and the proximity switch K1 is closed. At this time, the base voltage of the transistor Q1 is lower than 0.7V, the transistor Q1 is not turned on, and the capacitor C1 starts to charge; as the capacitor voltage gradually increases, the base voltage of the transistor Q1 gradually increases. When the base voltage of the transistor Q1 exceeds 0.7V, the transistor Q1 is turned on, the light emitting diode D1 is turned on, and when the light of the light emitting diode D1 irradiates the photodiode D2, the current can flow from the photodiode D2 to make the selection switch K2 start working, and the temperature sensors W1 to Wn are connected to the control circuit in sequence; when the temperature of any one of the temperature sensors increases, its resistance increases, so that the base voltage of the transistor Q2 gradually increases. When the base voltage of the transistor Q2 exceeds 0.7V, the transistor Q2 is turned on, and the gas sensor W starts to work; when the first movable fan 2 and When the second movable fan 3 leaves the ventilation channel, the proximity switch K1 is turned on, the capacitor C1 starts to discharge, and current still flows through the resistor R2. The control circuit continues to work for a period of time. When the voltage of the capacitor C1 drops below 0.7V, the transistor Q1 is turned off and the control circuit stops working; wherein: the fixed resistor R1 acts as a delay resistor and cooperates with the capacitor C1 to realize delayed opening when the control circuit is turned on; the fixed resistor R2 acts as a delay resistor and cooperates with the capacitor C1 to realize delayed closing when the control circuit is closed; the fixed resistor R3 and the resistor R5 play a current limiting role to prevent the control circuit from being damaged; the resistance of the fixed resistor R4 is higher than the maximum resistance of the temperature sensor, and it can cooperate with the temperature sensor to realize the control of the gas sensor W, so that it is turned on when the temperature reaches a preset value and turned off when the temperature is lower than the preset value, and the preset value is set according to the actual situation; the light-emitting diode D1 cooperates with the photodiode D2 to realize the opening or closing of the temperature sensor.

[0060] Furthermore, the method for detecting thermal runaway of a lithium battery cell provided in an embodiment of the present invention further includes:

[0061] The process of performing thermal runaway detection and positioning on the cells 7 distributed in a row on the first straight line portion includes:

[0062] Column initial state: the first movable fan 2 and the second movable fan 3 are respectively located at the ventilation channels on both sides of the last column of battery cells 7, and enter the column detection preparation state;

[0063] Column detection preparation state: when the first movable fan 2 and the second movable fan 3 move to the corresponding ventilation channel, the proximity switch at the corresponding ventilation channel is triggered, and they stay at the corresponding ventilation channel for a period of time, respectively, and after the abnormal thermal runaway gas diffused from other places in the early stage is blown away and the heat is dissipated, the control circuit set at the corresponding ventilation channel is turned on, and the column-by-column detection state or the column range detection state is entered;

[0064] Column-by-column detection state: the first movable fan 2 and the second movable fan 3 respectively move forward from both sides of the last column of battery cells 7 to detect the ventilation channels on both sides of each column of battery cells 7 one by one; wherein, in a certain column detection positioning: if the temperature sensor in the control circuit detects abnormal temperature, the abnormal row range where the thermal runaway battery cell 7 is located is determined and the gas sensor in the control circuit is turned on; if the gas sensor detects abnormal gas, the column where the thermal runaway battery cell 7 is located is located, and at the same time, the first movable fan 2 and the second movable fan 3 enter the row detection preparation state; if the gas sensor does not detect abnormal gas, the first movable fan 2 and the second movable fan 3 enter the row initial state;

[0065] Column range detection state: after the first movable fan 2 and the second movable fan 3 pass through the arc part and reach the first straight line part, the distance between the first movable fan 2 and the second movable fan 3 is adjusted to be equal to the distance between two adjacent proximity switches, and the first movable fan 2 and the second movable fan 3 are moved to the corresponding ventilation channel according to the abnormal column range, so that the first movable fan 2 and the second movable fan 3 are detected within the abnormal column range; if the gas sensor of the first movable fan 2 and the second movable fan 3 detects abnormal gas within the abnormal column range, the column where the thermal runaway battery cell 7 is located is determined, and the position of the thermal runaway battery cell 7 is determined according to the determined row and column where the thermal runaway battery cell 7 is located; if the gas sensor of the first movable fan 2 and the second movable fan 3 does not detect abnormal gas within the abnormal column range, the first movable fan 2 and the second movable fan 3 are moved to the column initial state;

[0066] The process of performing thermal runaway detection and positioning on the row-distributed battery cells 7 on the second straight line portion includes:

[0067] Row initial state: the first movable fan 2 and the second movable fan 3 are respectively located at the ventilation channels on both sides of the last row of battery cells 7, and enter the row detection preparation state;

[0068] Row detection preparation state: when the first movable fan 2 and the second movable fan 3 move to the corresponding ventilation channel, the proximity switch at the corresponding ventilation channel is triggered, and they stay at the corresponding ventilation channel for a period of time, respectively, and after the abnormal thermal runaway gas diffused from other places in the early stage is blown away and the heat is dissipated, the control circuit set at the corresponding ventilation channel is turned on, and the row-by-row detection state or the row range detection state is entered;

[0069] Row-by-row detection state: the first movable fan 2 and the second movable fan 3 respectively move forward from both sides of the last row of battery cells 7 to detect the ventilation channels on both sides of each row of battery cells 7 one by one; wherein, in the detection and positioning of a certain row: if the temperature sensor in the control circuit detects abnormal temperature, the abnormal column range where the thermal runaway battery cell 7 is located is determined and the gas sensor in the control circuit is turned on; if the gas sensor detects abnormal gas, the row where the thermal runaway battery cell 7 is located is located, and at the same time, the first movable fan 2 and the second movable fan 3 enter the column detection preparation state; if the gas sensor does not detect abnormal gas, the first movable fan 2 and the second movable fan 3 enter the column initial state;

[0070] Row range detection state: after the first movable fan 2 and the second movable fan 3 pass through the arc part and reach the second straight line part, the distance between the first movable fan 2 and the second movable fan 3 is adjusted to be equal to the distance between two adjacent proximity switches, and the first movable fan 2 and the second movable fan 3 are moved to the corresponding ventilation channel according to the abnormal row range, so that the first movable fan 2 and the second movable fan 3 are detected within the abnormal row range; if the gas sensor of the first movable fan 2 and the second movable fan 3 detects abnormal gas within the abnormal column range, the row where the thermal runaway battery cell 7 is located is determined, and the position of the thermal runaway battery cell 7 is determined according to the determined row and column where the thermal runaway battery cell 7 is located; if the gas sensor of the first movable fan 2 and the second movable fan 3 does not detect abnormal gas within the abnormal column range, the first movable fan 2 and the second movable fan 3 move to the row initial state.

[0071] After the first movable fan 2 and the second movable fan 3 of the embodiment of the present invention are positioned on both sides of the first row or the first column of battery cells, they always remain relatively still during movement. When the two movable fans are located at the first straight section of the U-shaped slide rail 1, they can cooperate with the control circuit to detect the column where the thermal runaway battery cells 7 are located. When the two movable fans are located at the second straight section of the U-shaped slide rail 1, they can cooperate with the control circuit to detect the row where the thermal runaway battery cells 7 are located. The distance between the two movable fans will be determined by the proximity switch when the two movable fans pass through the arc section of the U-shaped slide rail 1 and reach both sides of the first column of battery cells 7 or the first row of battery cells 7. When the distance between the two movable fans is determined, the two movable fans remain relatively still when moving on the straight section of the U-shaped slide rail 1, so as to ensure that the two adjacent proximity switches on both sides of a row or a column of battery cells 7 are triggered at the same time, that is, the control circuits on both sides of a column or a row of battery cells 7 are triggered at the same time.

[0072] When the movable fan of the embodiment of the present invention moves to the corresponding ventilation channel, on the ventilation channel where the movable fan stays, the gas and temperature released by the early thermal runaway battery cells in other places may diffuse to the ventilation channel. Then, when the two movable fans move to the corresponding ventilation channel, the control circuit will not work immediately, but will first charge the capacitor in the control circuit. At this time, the two movable fans can blow away the abnormal gas and heat diffused from other places, so that the influence of heat and interfering gas from other places on the detection is reduced. In addition, since the movable fan will stay for a period of time, it will leave enough detection time for the temperature sensor and the gas sensor, making the detection more accurate. Furthermore, by jointly determining whether thermal runaway occurs through the temperature sensor and the gas sensor detection, the accuracy of thermal runaway positioning can be effectively improved, and the two movable fans can simultaneously detect the ventilation channels on both sides of a column or a row of battery cells, so as to directly locate the thermal runaway problem of a column or a row of battery cells, thereby improving the detection speed.

[0073] As for the detection method embodiment of the second aspect, since it is basically similar to the system embodiment of the first aspect, the description is relatively simple, and the relevant parts may refer to the partial description of the system embodiment of the first aspect.

[0074] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0075] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art may understand and implement other variations of the disclosed embodiments by viewing the specification and its drawings. In the specification, the word "comprising" does not exclude other components or steps, and "a" or "one" does not exclude multiple situations. Certain measures are recorded in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

[0076] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A lithium battery module thermal runaway detection system, characterized in that: The system comprises: A lithium battery module, wherein a plurality of battery cells are arranged in rows and columns, and a control circuit is arranged at each ventilation channel between adjacent battery cells; a U-shaped slide rail, wherein the U-shaped slide rail comprises a first straight line portion and a second straight line portion connected by an arc portion, wherein the first straight line portion is arranged on one side of all battery cells arranged in the columns, and the second straight line portion is arranged on one side of all battery cells arranged in the rows, wherein the battery cells in the first column are close to the second straight line portion, and the battery cells in the first row are close to the first straight line portion, and wherein a first movable fan and a second movable fan are arranged on the U-shaped slide rail, wherein the first movable fan and the second movable fan move horizontally on the first straight line portion or the second straight line portion at the same time; wherein, Each control circuit includes a proximity switch K1, a temperature sensor W1 to a temperature sensor Wn, a gas sensor W, a transistor Q1, a transistor Q2, resistors R1 to R5, a light emitting diode D1, a photodiode D2, a selection switch K2, and a capacitor C1; wherein one end of the proximity switch K1, one end of the resistor R3, one end of the resistor R4, and one end of the resistor R5 are all connected to a power supply, the other end of the proximity switch K1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to one end of the resistor R2 and one end of the capacitor C1, the other end of the capacitor C1, the emitter of the transistor Q1, one end of the temperature sensor W1 to the temperature sensor Wn, and the transistor The emitter of the transistor Q2 is grounded, the other end of the resistor R2 is connected to the base of the transistor Q1, the collector of the transistor Q1 is connected to the cathode of the light-emitting diode D1, the anode of the light-emitting diode D1 is connected to the other end of the resistor R3, the other end of the resistor R4 is connected to the cathode of the photodiode D2, the anode of the photodiode D2 is connected to the base of the transistor Q2 and one end of the selection switch K2, the other end of the selection switch K2 is connected to the other end of any temperature sensor selected from the temperature sensor W1 to the temperature sensor Wn, the other end of the resistor R5 is connected to one end of the gas sensor W, and the other end of the gas sensor W is connected to the collector of the transistor Q2.

2. The battery cell thermal runaway detection system of the lithium battery module according to claim 1, characterized in that: The first straight line portion and the second straight line portion are both provided with a plurality of small holes at intervals, and each small hole is opposite to a ventilation channel, so that the first movable fan and the second movable fan can trigger the corresponding proximity switch K1 when they move to the small hole.

3. The battery cell thermal runaway detection system of the lithium battery module according to claim 1, characterized in that: The first movable fan and the second movable fan have the same structure; the first movable fan comprises a first micro motor, a first micro reducer, a fan and a pulley; wherein, The fan is mounted on the first micro motor, the first micro motor is connected to the first micro reducer, and the first micro reducer drives the pulley to move horizontally on the U-shaped slide rail.

4. The thermal runaway detection system for a lithium battery module according to claim 1, characterized in that: Each battery cell is provided with an active windshield; the active windshield comprises a windshield A surface, a central axis and a windshield B surface; wherein, The windshield B surface is fixedly mounted on the surface of the corresponding battery cell; the windshield A surface rotates around the central axis along with the flow of gas to close the ventilation channel perpendicular to the wind direction.

5. The battery cell thermal runaway detection system of the lithium battery module according to claim 1, characterized in that: Two temperature sensors are installed on the surface of each battery cell, one temperature sensor is used in the control circuit set at the corresponding ventilation channel of the row distribution, and the other temperature sensor is used in the control circuit set at the corresponding ventilation channel of the column distribution.

6. The battery cell thermal runaway detection system of the lithium battery module according to claim 1, characterized in that: In the control circuit set at each ventilation channel, the proximity switch K1 is installed on the side wall of the lithium battery module opposite to the corresponding ventilation channel, the temperature sensors W1 to Wn are installed on the surface of the corresponding battery cell, the gas sensor W is installed at the end of the corresponding ventilation channel, and the transistor Q1, the transistor Q2, the resistor R1 to the resistor R5, the light-emitting diode D1, the photodiode D2, the selection switch K2, and the capacitor C1 are integrated and installed on the lower surface of the lithium battery module at the corresponding ventilation channel.

7. The battery cell thermal runaway detection system of the lithium battery module according to claim 1, characterized in that: The selector switch K2 in each control circuit includes a rotating component, a second micro motor, a second micro reducer and a base; wherein, The base is fixedly mounted on the lower surface of the lithium battery module at the ventilation channel corresponding to the control circuit. The second micro motor is installed on the base. The second micro motor is connected to the second micro reducer. The second micro reducer drives the rotating component to rotate so that the rotating component can select to connect to any one of the temperature sensors W1 to Wn; wherein, the transistor Q1, the transistor Q2, the resistors R1 to R5, the light-emitting diode D1, the photodiode D2, and the capacitor C1 are integrated and installed in the base.

8. The battery cell thermal runaway detection system of the lithium battery module according to claim 1, characterized in that: An air outlet is arranged around the gas sensor W installed at the end of each ventilation channel; wherein, When the first movable fan and the second movable fan pass through the corresponding ventilation channels, the wind direction faces the gas sensor W and flows out through the air outlet around the gas sensor W.

9. A method for detecting thermal runaway of a lithium battery module, characterized in that: The battery cell thermal runaway detection system applied to the lithium battery module according to any one of claims 1 to 8, and the corresponding detection method includes: When the first movable fan and the second movable fan are respectively moved to the ventilation channel, the corresponding proximity switch K1 is triggered, and the proximity switch K1 is closed. At this time, the transistor Q1 is not turned on, and the capacitor C1 starts to charge; As the voltage of capacitor C1 gradually increases, transistor Q1 is turned on, and light-emitting diode D1 is turned on; when the light of light-emitting diode D1 irradiates photodiode D2, current flows through photodiode D2, causing selection switch K2 to start working, and temperature sensors W1 to Wn are connected to the control circuit in sequence; When the resistance of any temperature sensor among the temperature sensors W1 to Wn increases, the transistor Q2 is turned on and the gas sensor W starts to work. When the first movable fan and the second movable fan leave the ventilation channel respectively, the corresponding proximity switch K1 is opened, the capacitor C1 starts to discharge, and current still flows through the resistor R2, and the control circuit continues to work for a period of time; when the voltage of the capacitor C1 drops to the point where the transistor Q1 is cut off, the temperature sensors W1 to Wn and the gas sensor W are all turned off, and the control circuit stops working.

10. The method for detecting thermal runaway of a lithium battery module according to claim 9, characterized in that: The detection method further comprises: The process of performing thermal runaway detection and positioning on the cells distributed in a row on the first straight line portion includes: Column initial state: the first movable fan and the second movable fan are respectively located at the ventilation channels on both sides of the last column of cells, entering the column detection preparation state; Column detection preparation state: when the first movable fan and the second movable fan move to the corresponding ventilation channel, the proximity switch at the corresponding ventilation channel is triggered, and they stay at the corresponding ventilation channel for a period of time, respectively, and after the abnormal thermal runaway gas diffused from other places in the early stage is blown away and the heat is dissipated, the control circuit set at the corresponding ventilation channel is turned on, and the column-by-column detection state or the column range detection state is entered; Column-by-column detection state: the first movable fan and the second movable fan respectively move forward from both sides of the last column of battery cells to detect the ventilation channels on both sides of each column of battery cells one by one; wherein, in a certain column detection positioning: if the temperature sensor in the control circuit detects abnormal temperature, the abnormal row range where the thermal runaway battery cell is located is determined and the gas sensor in the control circuit is turned on; if the gas sensor detects abnormal gas, the column where the thermal runaway battery cell is located is located, and at the same time, the first movable fan and the second movable fan enter the row detection preparation state; if the gas sensor does not detect abnormal gas, the first movable fan and the second movable fan enter the row initial state; Column range detection state: after the first movable fan and the second movable fan pass through the arc part and reach the first straight line part, adjust the distance between the first movable fan and the second movable fan to be equal to the distance between two adjacent proximity switches, and move the first movable fan and the second movable fan to the corresponding ventilation channel according to the abnormal column range, so that the first movable fan and the second movable fan can detect within the abnormal column range; if the gas sensors of the first movable fan and the second movable fan detect abnormal gas within the abnormal column range, determine the column where the thermal runaway cell is located, and determine the position of the thermal runaway cell according to the row and column where the thermal runaway cell is located; if the gas sensors of the first movable fan and the second movable fan do not detect abnormal gas within the abnormal column range, the first movable fan and the second movable fan move to the column initial state; The process of performing thermal runaway detection and positioning on the row-distributed cells on the second straight line portion includes: Row initial state: the first movable fan and the second movable fan are respectively located at the ventilation channels on both sides of the last row of cells, entering the row detection preparation state; Row detection preparation state: when the first movable fan and the second movable fan move to the corresponding ventilation channel, the proximity switch at the corresponding ventilation channel is triggered, and they stay at the corresponding ventilation channel for a period of time, respectively, and after the abnormal thermal runaway gas diffused from other places in the early stage is blown away and the heat is dissipated, the control circuit set at the corresponding ventilation channel is turned on, and the row-by-row detection state or the row range detection state is entered; Row-by-row detection state: the first movable fan and the second movable fan respectively move forward from both sides of the last row of battery cells to detect the ventilation channels on both sides of each row of battery cells one by one; wherein, in the detection and positioning of a certain row: if the temperature sensor in the control circuit detects abnormal temperature, the abnormal column range where the thermal runaway battery cell is located is determined and the gas sensor in the control circuit is turned on; if the gas sensor detects abnormal gas, the row where the thermal runaway battery cell is located is located, and at the same time, the first movable fan and the second movable fan enter the column detection preparation state; if the gas sensor does not detect abnormal gas, the first movable fan and the second movable fan enter the column initial state; Row range detection state: after the first movable fan and the second movable fan pass through the arc part and reach the second straight line part, adjust the distance between the first movable fan and the second movable fan to be equal to the distance between two adjacent proximity switches, and move the first movable fan and the second movable fan to the corresponding ventilation channel according to the abnormal row range, so that the first movable fan and the second movable fan can be detected within the abnormal row range; if the gas sensors of the first movable fan and the second movable fan detect abnormal gas within the abnormal column range, determine the row where the thermal runaway cell is located, and determine the position of the thermal runaway cell according to the determined row and column where the thermal runaway cell is located; if the gas sensors of the first movable fan and the second movable fan do not detect abnormal gas within the abnormal column range, the first movable fan and the second movable fan move to the row initial state.

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