Thermoelectrically separated battery pack

Abstract

The application provides a thermoelectric separation type battery pack, which comprises a first fireproof plate, a second fireproof plate and a battery pack, the battery pack is internally provided with a plurality of battery monomers, the upper side of each battery monomer is provided with a pressure relief valve, a plurality of through holes are formed in the first fireproof plate, the pressure relief valves arranged on the battery monomers correspond to the through holes one by one and are arranged in the corresponding through holes respectively, the upper side of the first fireproof plate is provided with an absorber, the second fireproof plate is arranged on the upper side of the absorber, and the battery pack is further provided with a detection system. The application solves the problem that, in the prior art, when battery thermal runaway occurs, liquid and solid sprayed from the blocked pressure relief valve cause short circuit of the positive electrode and the negative electrode of the electrode, arc discharge, ignition of high-temperature gas and battery fire or even explosion.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle technology, and in particular to a thermoelectric separation battery pack. Background Technology

[0002] In new energy vehicles, the battery pack provides the power needed by the vehicle. The battery pack is composed of multiple battery cells connected in series and parallel to form a battery module. Multiple modules are then connected in series and parallel to form a battery module, and a fireproof plate / film is covered on top of the battery module.

[0003] Since the entire operation of a new energy vehicle is powered by a battery pack, which needs to store a large amount of electricity, the battery pack is easily affected by factors such as external temperature and improper vehicle use, leading to malfunctions. Battery thermal runaway is the most common battery pack failure. When battery thermal runaway occurs, the internal pressure in the battery cell increases due to the rise in temperature. High-temperature gases, liquids, and solids are ejected from the pressure relief valve. In existing technology, the function of the fireproof plate / membrane is to prevent the high-temperature gases, liquids, and solids ejected from the pressure relief valve from affecting the vehicle floor and causing a fire. However, the gases ejected from the pressure relief valve are flammable, and the ejected liquids and solids are conductive. Due to the function of the fireproof plate / membrane, the liquids and solids will be coated on the electrodes and electrode connecting pieces, causing a short circuit between the positive and negative electrodes and arcing. The high-temperature arc will instantly ignite the high-temperature gases already ejected from the pressure relief valve, thereby causing the battery to catch fire or even explode. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a thermoelectric separation battery pack, which solves the problem that in the event of battery thermal runaway, liquid and solid ejected from the pressure relief valve cause short circuits between the positive and negative electrodes, resulting in arc discharge, ignition of high-temperature gases, and even battery fire or explosion.

[0005] According to an embodiment of the present invention, a thermoelectric separation battery pack includes a first fireproof plate, a second fireproof plate, and a battery pack. The battery pack contains a plurality of battery cells, each of which has a pressure relief valve on its upper side. The first fireproof plate has a plurality of through holes, and the pressure relief valves on each battery cell correspond one-to-one with the through holes and are respectively disposed in the corresponding through holes. An absorber is disposed on the upper side of the first fireproof plate, and the second fireproof plate is disposed on the upper side of the absorber. The battery pack also contains a detection system.

[0006] Preferably, the pressure relief valve is fixedly fitted with two limiting rings on its outer side, which respectively abut against the upper and lower sides of the first fireproof plate.

[0007] Preferably, an adhesive plate is provided on the upper side of the first fireproof board and the lower side of the second fireproof board.

[0008] Preferably, the absorber includes an air pipe, an absorption ring, an air pump, and an absorption box. The absorption ring has two air holes that penetrate the inner and outer sides. Each air hole is connected to an air pipe at the end near the outer side of the absorption ring. The free end of one of the air pipes is connected to the air inlet of the air pump, and the air outlet of the air pump is connected to the absorption box.

[0009] Preferably, the detection system includes a pneumatic pressure sensor, a pressure sensor, a controller, an electromagnetic switch, and a low-voltage power supply. The pneumatic pressure sensor is located on the upper side of the first fireproof plate, and a pressure sensor is provided between each battery cell. The pneumatic pressure sensor and the pressure sensor are electrically connected to the controller. The low-voltage power supply is electrically connected to the controller and the electromagnetic switch. The electromagnetic switch is also electrically connected to the air pump.

[0010] Preferably, the controller acquires the pressure values ​​of the air pressure sensor and the pressure sensor at fixed intervals, and calculates the safety score of the battery pack based on the current pressure values ​​of the air pressure sensor and the pressure sensor. If the safety score is less than a first threshold, the controller controls the electromagnetic switch to close and starts the air pump.

[0011] Preferably, the formula for calculating the safety score is as follows:

[0012]

[0013] Where S is the safety score, x1 is the pressure value of the pressure sensor, x2 is the pressure value of the air pressure sensor, and k is a constant.

[0014] Preferably, after the air pump is started, if the safety score calculated by the controller multiple times in a row is less than the first threshold, a first warning signal is generated.

[0015] If the safety score calculated by the controller is greater than the first threshold and less than the second threshold for multiple consecutive times, the controller will disconnect the electromagnetic switch and generate a second warning signal.

[0016] When the safety score calculated by the controller is greater than the second threshold, the control electromagnetic switch is disconnected.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] When a battery cell experiences thermal runaway, the solids and liquids ejected from the pressure relief valve coat the upper side of the first fireproof plate and the lower side of the second fireproof plate, preventing them from contacting the motor on the battery cell and generating an electric arc. The ejected high-temperature gas is absorbed by the absorber, thus directly preventing the battery from catching fire or exploding. Attached Figure Description

[0019] Figure 1 This is an exploded view of the battery pack structure according to an embodiment of the present invention.

[0020] Figure 2 This is a structural diagram of the pressure relief valve according to an embodiment of the present invention.

[0021] Figure 3 Embodiments of the present invention Figure 1 A cross-sectional view at position A in the middle.

[0022] Figure 4 This is a diagram of the detection system architecture according to an embodiment of the present invention.

[0023] In the above attached figures: 1. First fireproof plate; 2. Absorption ring; 3. Second fireproof plate; 4. Through hole; 5. Pressure relief valve; 6. Air pipe; 7. Air pressure sensor; 8. Battery cell; 9. Battery pack; 10. Air pump; 11. Absorption box; 12. Limiting ring; 13. Pressure sensor. Detailed Implementation

[0024] The technical solutions of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] like Figure 1 As shown in the figure, this embodiment of the invention proposes a thermoelectric separation battery pack, including a first fireproof plate 1, a second fireproof plate 3, and a battery pack 9. The battery pack 9 contains multiple battery cells 8, and each battery cell 8 has a pressure relief valve 5 on its upper side. The first fireproof plate 1 has multiple through holes 4, and the pressure relief valves 5 on each battery cell 8 correspond one-to-one with the through holes 4 and are respectively installed in the corresponding through holes 4. Two limiting rings 12 are fixedly sleeved on the outside of the pressure relief valves 5 and abut against the upper and lower sides of the first fireproof plate 1 respectively. An absorber is provided on the upper side of the first fireproof plate 1, and the second fireproof plate 3 is provided on the upper side of the absorber. The battery pack 9 also contains a detection system. Adhesive plates are provided on the upper side of the first fireproof plate 1 and the lower side of the second fireproof plate 3. The adhesive plates can adhere to most solids and liquids in the air, preventing a large amount of solids and liquids from being absorbed by the absorber and clogging various pipes in the absorber when absorbing high-temperature gas.

[0026] When a battery cell 8 experiences thermal runaway, the solids and liquids ejected from the pressure relief valve 5 will coat the upper side of the first fireproof plate 1 and the lower side of the second fireproof plate 3, preventing them from contacting the motor on the battery cell 8 and generating an electric arc. The ejected high-temperature gas will be absorbed by the absorber, thus directly preventing the battery from catching fire or exploding. In addition, under the action of the two limiting rings 12, the gap between the opening and the pressure relief valve 5 will be directly sealed, preventing the high-temperature gas, solids and liquids from contacting the battery cell 8.

[0027] The absorber includes a duct 6, an absorption ring 2, an air pump 10, and an absorption box 11. The absorption ring 2 has two air holes that penetrate both the inner and outer sides. Each air hole is connected to the duct 6 at the end near the outer side of the absorption ring 2. The free end of one duct 6 is connected to the air inlet of the air pump 10, and the other duct 6 is connected to the outside air. The air outlet of the air pump 10 is connected to the absorption box 11, which contains an absorbent for absorbing gases.

[0028] When a single battery cell 8 experiences thermal runaway, the high-temperature gas ejected from the pressure relief valve 5 enters the gap between the first fireproof plate 1 and the second fireproof plate 3. When there is a small amount of high-temperature gas, the air pump 10 will not be activated to absorb it, and a small amount of high-temperature gas will escape from the air pipe 6 connected to the outside. When there is a large amount of high-temperature gas, if it escapes to the outside, it will raise the temperature of the environment around the battery pack 9, thus affecting the operation of the battery pack 9. Therefore, the air pump 10 will be activated to absorb the high-temperature gas. At this time, the high-temperature gas will be drawn into the air pump 10 and enter the absorption box 11 to be absorbed by the absorbent. At the same time, after the high-temperature gas is drawn away by the air pump 10, the ambient temperature air from the outside enters the gap between the first fireproof plate 1 and the second fireproof plate 3 to fill it and cool down the battery pack 9.

[0029] The detection system includes a pressure sensor 7, a pressure sensor 13, a controller, an electromagnetic switch, and a low-voltage power supply. The pressure sensor 7 is located on the upper side of the first fireproof plate 1. A pressure sensor 13 is provided between each battery cell 8. The pressure sensor 7 and the pressure sensor 13 are electrically connected to the controller. The low-voltage power supply is electrically connected to the controller and the electromagnetic switch. The electromagnetic switch is also electrically connected to the air pump 10.

[0030] When a new energy vehicle is powered on, the BMS system on the vehicle monitors the battery pack 9. However, when the vehicle is powered off and turned off, the BMS system also shuts down, and it can no longer monitor the battery pack 9. Most fires in new energy vehicles occur when the vehicle is turned off. Therefore, the detection system in this invention is mainly designed to monitor the state of the battery pack 9 by a low-voltage power supply that can store electricity after the vehicle is powered off, through the air pressure sensor 7 and the pressure sensor 13, to determine whether the individual battery cells 8 in the battery pack 9 have thermal runaway. This determines whether the electromagnetic switch is closed or opened to start or stop the air pump 10. The electromagnetic switch is normally in the open state.

[0031] The controller acquires the pressure values ​​of pressure sensor 13 and air pressure sensor 7 at fixed time intervals, and calculates the safety score of battery pack 9 based on the current pressure values ​​of air pressure sensor 7 and pressure sensor 13. The calculation formula for the safety score is as follows:

[0032]

[0033] Where S is the safety score, x1 is the pressure value of the pressure sensor, x2 is the pressure value of the air pressure sensor, and k is a constant.

[0034] In this invention, according to the safety scoring formula, the safety score of battery pack 9 is controlled between 0 and 1. The smaller the safety score, the less safe battery pack 9 is, and the greater the probability of thermal runaway. Conversely, the larger the safety score, the safer battery pack 9 is, and the smaller the probability of thermal runaway.

[0035] When a battery cell 8 experiences thermal runaway, it is usually accompanied by expansion and deformation, which will compress the pressure sensor 13. If the battery does not experience thermal runaway, the pressure value of the pressure sensor 13 should be 0. Of course, external physical collisions may also cause the battery to deform to varying degrees, compressing the pressure sensor 13. The external environment will also affect the air pressure inside the battery pack 9, causing changes in the pressure value of the pressure sensor 13. Therefore, one cannot directly determine that the battery cell 8 has experienced thermal runaway based on changes in the pressure value of the pressure sensor 13 or the air pressure sensor 7.

[0036] In summary, if the safety score calculated by the controller is between 0.8 and 1, it indicates that the battery pack 9 is still in a safe state. At this time, the pressure value of the air pressure sensor 7 changes little. The reason for the change is that the change in ambient temperature causes the air pressure and temperature inside the battery pack 9 to change, while the pressure value of the pressure sensor 13 remains unchanged.

[0037] If the safety score is less than 0.8, it indicates that the battery pack 9 is in an unsafe state. The air pressure inside the battery pack 9 increases due to the rising temperature, and the pressure value of the air pressure sensor 7 begins to gradually increase. The higher temperature will affect the normal operation of the battery pack 9. At this time, the controller will immediately control the electromagnetic switch to close and start the air pump 10 to extract the gas inside the battery pack 9 and allow outside air to enter, forming ventilation and reducing the temperature inside the battery pack 9.

[0038] After the air pump 10 is started, the controller continues to acquire relevant data and calculate the safety score according to the original program. If the safety score calculated by the controller is less than the first threshold (0.8) multiple times (usually 3 to 5 times), it indicates that the air pressure in the battery pack 9 is too high or the battery cell 8 has expanded and deformed, indicating that thermal runaway has occurred. At this time, the first warning signal will be generated immediately.

[0039] If the safety score calculated by the controller is greater than the first threshold and less than the second threshold (0.85) for multiple consecutive times, it indicates that the battery pack 9 has expanded and deformed. However, the pressure relief valve 5 of the battery pack 9 has not released a lot of high-temperature gas and has not experienced thermal runaway, but other faults have occurred. At this time, the control solenoid switch is disconnected and a second warning signal is generated.

[0040] When the safety score calculated by the controller is greater than the second threshold, it indicates that the air pressure inside the battery pack 9 has temporarily increased due to the increase in the outside temperature. The battery pack 9 is still in good condition, and the control electromagnetic switch is disconnected at this time.

[0041] In addition, after the first and second warning signals are generated, they will be sent to the BMS system for relevant processing the next time the car is powered on and the BMS is started.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A thermoelectric separation battery pack, characterized in that: The battery pack includes a first fireproof plate, a second fireproof plate, and a battery pack. The battery pack contains multiple battery cells, each of which has a pressure relief valve on its upper side. The first fireproof plate has multiple through holes, and the pressure relief valves on each battery cell correspond one-to-one with the through holes and are respectively located in the corresponding through holes. An absorber is located on the upper side of the first fireproof plate, and the second fireproof plate is located on the upper side of the absorber. The battery pack also contains a detection system. Adhesive plates are located on the upper side of the first fireproof plate and the lower side of the second fireproof plate. The absorber includes a duct, an absorption ring, an air pump, and an absorption box. The absorption ring has two vents that penetrate both the inner and outer sides. Each vent is connected to a duct near the outer side of the absorption ring. The free end of one duct is connected to the air inlet of the air pump, and the free end of the other duct is connected to the outside air. The air outlet of the air pump is connected to the absorption box. The detection system includes a pneumatic pressure sensor, a pressure sensor, a controller, an electromagnetic switch, and a low-voltage power supply. The pneumatic pressure sensor is located on the upper side of the first fireproof plate, and a pressure sensor is provided between each battery cell. Both the pneumatic pressure sensor and the pressure sensor are electrically connected to the controller. The low-voltage power supply is electrically connected to the controller and the electromagnetic switch. The electromagnetic switch is also electrically connected to an air pump. The controller acquires the pressure values ​​of the pneumatic pressure sensor and the pressure sensor at fixed intervals and calculates the safety score of the battery pack based on the current pressure values ​​of the pneumatic pressure sensor and the pressure sensor. If the safety score is less than a first threshold, the controller controls the electromagnetic switch to close and starts the air pump.

2. The thermoelectric separation battery pack as described in claim 1, characterized in that: The pressure relief valve is fixedly fitted with two limiting rings on its outer side, which respectively abut against the upper and lower sides of the first fireproof plate.

3. The thermoelectric separation battery pack as described in claim 1, characterized in that: The formula for calculating the safety score is as follows: Where S represents the safety score. The pressure value of the pressure sensor. is the pressure value of the barometric pressure sensor, and k is a constant.

4. A thermoelectric separation battery pack as described in claim 1, characterized in that: After the air pump is started, if the safety score calculated by the controller is less than the first threshold for multiple consecutive times, a first warning signal is generated. If the safety score calculated by the controller is greater than the first threshold and less than the second threshold for multiple consecutive times, the controller will disconnect the electromagnetic switch and generate a second warning signal. When the safety score calculated by the controller is greater than the second threshold, the control electromagnetic switch is disconnected.

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