Vehicle battery pack thermal runaway detection device and battery cell

Abstract

The utility model provides a vehicle battery pack thermal runaway detection device and a battery cell. The thermal runaway detection device for the vehicle battery pack comprises a fixed rod arranged on an installation base, wherein a first contact is arranged on the installation base; a cavity is formed in the shell, and the shell is arranged in the thermal environment space of the battery pack and sleeves the fixed rod in a sliding and sealing manner; a second contact is arranged outside the shell, and the connection state between the first contact and the second contact can be detected; the filler is filled in the shell, and the volume of the filler is increased along with the increase of the temperature; and when the volume of the filler is increased to drive the shell to be far away from the mounting base, the second contact of the follow-up shell can be close to and communicated with the first contact. The utility model relates to a thermal runaway detection device for a vehicle battery pack. By arranging the filler, the thermal runaway fault of the battery pack is detected, so that the safety performance of the battery pack is improved, and the battery pack has good practicability.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicle battery packs, and particularly relates to a thermal runaway detection device for a vehicle battery pack. The utility model also relates to a battery cell provided with the above-mentioned thermal runaway detection device for a vehicle battery pack. Background Art

[0002] With the national planning and support for the development of the new energy vehicle industry, the market ownership of new energy vehicles has been continuously increasing, and pure electric or hybrid vehicles are becoming more and more popular in people's lives. Among them, the safety of the vehicle battery pack has become one of the important performance indicators of battery-powered vehicles. The battery pack contains multiple battery cells, which can generate electrical energy through electrochemical reactions and transmit it outside the battery pack to provide electrical energy for electric vehicles to drive the electric vehicles.

[0003] During the normal driving of an electric vehicle, when the battery pack continuously outputs electrical energy, heat is generated in the battery cells and the battery pack, and the battery pack needs to be maintained at a stable operating temperature. When the temperature of the battery pack is too high, that is, when the battery pack undergoes thermal runaway, the operating efficiency of the battery pack will decrease, and even damage and fire may occur. Therefore, the problems of over-temperature and thermal runaway of the battery cells have become the focus of the new energy vehicle industry.

[0004] Generally, in order to ensure the normal operation of the battery pack, the battery pack is usually equipped with a thermal runaway detection device, which is used to alarm and remind the driver when thermal runaway of the battery pack occurs. In the prior art, the thermal runaway detection device usually uses a temperature sensor and combines parameters such as the voltage of the battery pack to be detected by a microprocessing unit, and then judges whether the battery pack has thermal runaway. However, the connection condition of the wire harness pins of the temperature sensor will affect the acquisition value of the sensor, resulting in drift or deviation of the acquisition value. Therefore, during the long-term use of the battery pack, the above-mentioned thermal runaway detection device based on the temperature sensor is prone to false judgment and missed judgment of thermal runaway, thus reducing the safety of the battery pack. Summary of the Utility Model

[0005] In view of this, the purpose of the present utility model is to provide a thermal runaway detection device for a vehicle battery pack to detect the thermal runaway fault of the battery pack and improve the safety performance of the battery pack.

[0006] To achieve the above object, the technical solution of the present utility model is realized as follows:

[0007] A thermal runaway detection device for a vehicle battery pack, comprising: a fixing rod provided on an installation base, and a first contact is provided on the installation base; a housing with a cavity formed inside, the housing is arranged in the thermal environment space of the battery pack and is sleeved on the fixing rod in a sliding and sealing manner; a second contact is provided outside the housing, and the connection state between the first contact and the second contact can be detected; a filler filled in the housing, and the volume of the filler increases with the increase of temperature; when the housing is driven away from the installation base due to the increase in the volume of the filler, the second contact following the housing can approach and connect the first contact.

[0008] Further, a blocking portion extending radially along the fixing rod is provided on the fixing rod. When the housing is away from the installation base, the blocking portion gradually approaches and can abut against the inner wall of the top of the housing.

[0009] Further, a reset mechanism is provided between the fixing rod and the housing; when the volume of the filler decreases due to cooling, the reset mechanism drives the housing to approach the installation base.

[0010] Further, the reset mechanism is configured as an elastic member provided between the fixing rod and the housing, and the elastic member is compressed and stores energy when the housing is away from the installation base.

[0011] Further, the elastic member is a spring wound around the fixing rod.

[0012] Further, the filler is paraffin.

[0013] Further, a sealing ring sleeved on the fixing rod is fixed on the housing.

[0014] Further, a channel extending axially is formed in the fixing rod, and the channel communicates with the cavity.

[0015] Compared with the prior art, the present utility model has the following advantages:

[0016] For the thermal runaway detection device for a vehicle battery pack of the present utility model, by setting the filler and utilizing the characteristic that the volume of the filler increases with the increase of temperature, the volume of the filler increases due to the increase of temperature in the thermal environment space, and then the filler drives the second contact to connect the first contact, realizing the detection of the thermal runaway fault of the battery pack, thereby improving the safety performance of the battery pack and having good practicability.

[0017] A blocking portion is provided on the fixing rod. When the housing is away from the installation base, the blocking portion can gradually approach and abut against the inner wall of the top of the housing, and can keep the housing on the fixing rod to prevent the housing from separating from the fixing rod.

[0018] A reset mechanism is provided between the fixed rod and the housing. When the filling material reduces in volume due to cooling, the reset mechanism can drive the housing closer to the installation base. Thus, when the temperature in the thermal environment space drops and is lower than the preset value, the housing and the second contact can be made to approach the installation base, and the first contact and the second contact can be disconnected.

[0019] The reset mechanism is configured as an elastic member disposed between the fixed rod and the housing. The elastic member is compressed and stores energy when the housing moves away from the installation base. Using an elastic member as the reset mechanism has a simple and reliable structure and can effectively drive the housing and the second contact closer to the installation base when the filling body cools.

[0020] The elastic member is a spring wound around the fixed rod. It has a simple structure, can effectively achieve the reset effect, and using a spring wound around the fixed rod can reduce the occupation of the inner cavity space of the housing, thereby increasing the filling amount of the filling material.

[0021] Paraffin is used as the filling material in the housing cavity. It is in a solid state at normal temperature, which is convenient for filling in the housing and can prevent leakage from the housing. At the same time, paraffin can melt when the battery pack is out of thermal control, increasing its volume, thereby effectively pushing the housing to move. Also, the temperature at which this detection device is triggered can be controlled by selecting paraffins of different grades.

[0022] A sealing ring sleeved on the fixed rod is fixed to the housing. By providing this sealing ring, the sealing performance between the housing and the fixed rod can be improved, thereby preventing the filling material from overflowing through the gap between the housing and the fixed rod when its volume increases due to heating, which would cause the failure of this detection device.

[0023] A channel communicating with the cavity is formed in the fixed rod. Through the setting of this channel, when the filling material expands, it can simultaneously push against the installation base and the housing through this channel, enabling the housing to be effectively driven by the filling material to move away from the installation base.

[0024] Another object of the present utility model is to provide a battery cell, which includes a battery cell housing, a pole group disposed in the battery cell housing, and a battery cell cover plate for closing the battery cell housing. The battery cell housing is configured with the vehicle battery pack thermal runaway detection device as described above.

[0025] Further, the installation base is the battery cell cover plate.

[0026] The battery cell of the present utility model and the vehicle battery pack thermal runaway detection device as described above have the same beneficial effects as compared with the prior art, and will not be elaborated herein. Description of the Drawings

[0027] The accompanying drawings, which form a part of the present utility model, are used to provide a further understanding of the present utility model. The schematic embodiments and descriptions thereof of the present utility model are used to explain the present utility model and do not constitute an improper limitation to the present utility model. In the drawings:

[0028] Figure 1 is a schematic diagram of the overall structure of the vehicle battery pack thermal runaway detection device according to the first embodiment of the present utility model;

[0029] Figure 2 is a schematic diagram of the internal structure of the vehicle battery pack thermal runaway detection device according to the first embodiment of the present utility model when not triggered;

[0030] Figure 3 is a schematic diagram of the internal structure of the vehicle battery pack thermal runaway detection device according to the first embodiment of the present utility model when triggered;

[0031] Explanation of reference numerals:

[0032] 1. Fixed rod; 101. Blocking part; 102. Channel; 103. Elastic member;

[0033] 2. Installation base; 201. First contact; 202. First connection part;

[0034] 3. Housing; 301. Second contact; 302. Second connection part; 303. Sealing ring; 304. Protrusion;

[0035] 4. Filler; 5. Cell cover plate. Detailed implementation manners

[0036] It should be noted that, without conflict, the embodiments in the present utility model and the features in the embodiments can be combined with each other.

[0037] In the description of the present utility model, it should be noted that if terms indicating orientation or positional relationship such as "upper", "lower", "inner", "outer", etc. appear, they are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present utility model. In addition, if terms such as "first", "second", etc. appear, they are also only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0038] In addition, in the description of the present utility model, unless otherwise clearly defined, the terms "installation", "connection", "connection", and "connector" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood in combination with specific situations.

[0039] The present utility model will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0040] Embodiment 1

[0041] This embodiment relates to a vehicle battery pack thermal runaway detection device for detecting the thermal runaway fault of the battery pack. In terms of the overall structure, as shown in Figure 1 、 Figure 2 and Figure 3 , the vehicle battery pack thermal runaway detection device of this embodiment includes a fixing rod 1, a housing 3, a filler 4, a first contact 201, and a second contact 301.

[0042] Among them, the fixing rod 1 is arranged on an installation base 2, and the first contact 201 is provided on the installation base 2.

[0043] A cavity is formed inside the housing 3. The housing 3 is arranged in the thermal environment space of the battery pack and is slidably and sealedly sleeved on the fixing rod 1. A second contact 301 is provided outside the housing 3, and the connection state between the first contact 201 and the second contact 301 can be detected.

[0044] The filler 4 is filled in the housing 3, and the volume of the filler 4 increases with the increase of temperature. When the housing 3 is driven away from the installation base 2 due to the increase in the volume of the filler 4, the second contact 301 following the movement of the housing 3 can approach and connect with the first contact 201.

[0045] It can be understood that the housing 3 is sleeved on the fixing rod 1 and can move along the length direction of the fixing rod 1 away from or close to the installation base 2. When the housing 3 approaches the installation base 2, a part of the fixing rod 1 is located in the cavity of the housing 3 and occupies part of the volume of the cavity. At this time, the volume of the cavity is small. When the housing 3 moves away from the installation base 2, a part of the fixing rod 1 leaves the cavity, and at this time, the volume of the cavity becomes larger. Since the volume of the filler 4 changes with the change of temperature, when the volume of the filler 4 increases, the filler 4 drives the housing 3 away from the installation base 2, so that the volume of the cavity increases to accommodate the filler 4.

[0046] When the temperature of the thermal environment space inside the battery pack rises to a preset value, the volume of the filler 4 increases and drives the housing 3 to move, causing the first contact 201 to communicate with the second contact 301. At this time, the thermal runaway detection device of the vehicle battery pack in this embodiment is in a triggered state, indicating that the temperature inside the battery pack is too high and the battery pack is in a thermal runaway state.

[0047] When the temperature of the thermal environment space inside the battery pack does not reach the preset value, the first contact 201 and the second contact 301 are disconnected. At this time, the thermal runaway detection device of the vehicle battery pack in this embodiment is in an untriggered state, indicating that the battery pack is working properly.

[0048] As described above, by arranging the filler 4 inside the housing 3 and utilizing the characteristic that the volume of the filler 4 increases with the increase of temperature, the volume of the filler 4 increases due to the increase of temperature in the thermal environment space, and then the filler 4 drives the second contact 301 to communicate with the first contact 201, realizing the detection of the thermal runaway fault of the battery pack, thereby improving the safety performance of the battery pack and having good practicability.

[0049] Based on the above overall introduction, specifically, the housing 3 of this embodiment is a cylindrical structure with an opening at one end for sleeving on the fixing rod 1. And the housing 3 can preferably be made of a metal material, which has good heat conduction performance, enabling the heat in the thermal environment space to be quickly and accurately conducted to the filler 4 in the housing 3, improving the detection sensitivity of the thermal runaway detection device of this vehicle battery pack. In addition, both the first contact 201 and the second contact 301 are electrically connected to the micro control unit of the vehicle, that is, the MCU. By detecting the communication state between the first contact 201 and the second contact 301 through the micro control unit, it is thus possible to judge whether the battery pack has a thermal runaway through the communication state between the first contact 201 and the second contact 301.

[0050] To prevent the housing 3 from falling off the fixing rod 1 when moving, resulting in the failure of this detection device. As Figure 2 and Figure 3 shown, the fixing rod 1 of this embodiment is provided with a blocking portion 101 extending radially along the fixing rod 1. When the housing 3 is away from the mounting base 2, the blocking portion 101 gradually approaches and can abut against the inner wall of the top of the housing 3, capable of keeping the housing 3 on the fixing rod 1 and preventing the housing 3 from detaching from the fixing rod 1, resulting in the failure of this detection device.

[0051] After the vehicle battery pack thermal runaway detection device in this embodiment is triggered, if the temperature in the thermal environment space inside the battery pack decreases and the thermal runaway fault of the battery pack is eliminated, this detection device should be switched to the untriggered state. To achieve the above effect, a reset mechanism is provided between the fixed rod 1 and the housing 3 in this embodiment. When the battery pack exits the thermal runaway state, the filler 4 in the housing 3 cools due to the decrease in the temperature in the thermal environment space inside the battery pack, and thus the volume of the filler 4 decreases. The reset mechanism can drive the housing 3 closer to the mounting base 2, so that the volume of the cavity of the housing 3 decreases as the volume of the filler 4 decreases. When the housing 3 moves, the second contact 301 disconnects from the first contact 201 as the housing 3 moves, and thus the vehicle battery pack thermal runaway detection device in this embodiment is restored to the untriggered state.

[0052] To further improve the reliability of the reset mechanism in driving the housing 3 to move, the reset mechanism is configured as an elastic member 103 provided between the fixed rod 1 and the housing 3. The elastic member 103 can be compressed and store energy when the housing 3 moves away from the mounting base 2. When the volume of the filler 4 decreases, the elastic member 103 can release energy and push the housing 3 closer to the mounting base 2, thereby achieving the disconnection of the first contact 201 and the second contact 301.

[0053] Specifically, to ensure the reliability of the elastic member 103, the elastic member 103 is a spring wound around the fixed rod 1. Its structure is simple and can effectively achieve the above-mentioned reset function. In specific implementation, both ends of the spring respectively abut against the blocking portion 101 of the fixed rod 1 and the inner wall of the housing 3, so as to achieve the compression and energy storage of the spring when the housing 3 moves away from the mounting base 2.

[0054] To make the filler 4 increase in volume as the temperature rises, so that the vehicle battery pack thermal runaway detection device in this embodiment can be triggered at a preset temperature value, the filler 4 in this embodiment is paraffin. It can be understood that paraffin is in a solid state at room temperature. The solid paraffin is convenient for filling in the housing 3, and compared with the liquid filler 4, it is not easy to leak from the housing 3, thus facilitating production and manufacturing. At the same time, the melting point of paraffin is about 47 - 64 °C. When the solid paraffin melts into a liquid state, the volume change is obvious, and it can effectively drive the housing 3 to move. In addition, the temperature range at which paraffin melts is close to the temperature range of battery pack thermal runaway, and various paraffins are divided into different varieties and grades every 2 °C according to the melting point. By selecting a suitable grade of paraffin, the melting temperature of paraffin can correspond to the battery pack thermal runaway temperature, so as to achieve the effect of accurately detecting the thermal runaway fault. In specific implementation, the filler 4 in this embodiment uses No. 60 paraffin, which melts when the temperature in the battery pack thermal environment space reaches 60 °C.

[0055] To ensure the sealing between the housing 3 and the fixed rod 1, so as to prevent the filler 4 from leaking due to the increase in volume, such asFigure 2 and Figure 3 As shown in Figure 3 , a sealing ring 303 sleeved on the fixing rod 1 is fixed on the housing 3 of this embodiment, thereby improving the sealing performance between the housing 3 and the fixing rod 1. In specific implementation, for the convenience of setting the sealing ring 303, one end of the housing 3 close to the installation base 2, that is, the end sleeving the fixing rod 1, is provided with a protruding block 304 that protrudes outward and is slidably sleeved on the fixing rod 1, and the sealing ring 303 is embedded in the protruding block 304. At the same time, the first contact 201 is connected to the installation base 2 through an L-shaped first connecting portion 202, and the second contact 301 is connected to the protruding block 304 through a rod-shaped second connecting portion 302, so as to realize the connection between the second contact 301 following the movement of the housing 3 and the protruding block 304 and the first contact 201.

[0056] In order to ensure that when the filler 4 increases in volume, it can effectively push the housing 3 and the fixing rod 1, so that the housing 3 moves away from the installation base 2, a channel 102 extending axially is formed in the fixing rod 1 of this embodiment, and the channel 102 communicates with the cavity of the housing 3. Through the setting of this channel 102, when the filler 4 increases in volume or melts, part of the filler 4 can enter the channel 102 and push the housing 3 away from the installation base 2. At the same time, when the filler 4 decreases in volume due to cooling, part of the filler 4 can remain in the channel 102, so that there is enough space in the cavity for part of the fixing rod 1 to enter, so that the housing 3 can return to the initial position.

[0057] In summary, the thermal runaway detection device for a vehicle battery pack of this embodiment sets the filler 4 in the housing 3. By using the characteristic that the filler 4 increases in volume due to the increase in temperature, the filler 4 increases in volume due to the increase in temperature in the thermal environment space, and then the filler 4 drives the housing 3 to move, so as to connect the second contact 301 with the first contact 201, and by detecting the connection state of the first contact 201 and the second contact 301, the detection of the thermal runaway fault of the battery pack is realized, thereby improving the safety performance of the battery pack and having good practicability.

[0058] Embodiment Two

[0059] This embodiment relates to an electric core, which is arranged in a battery pack to output electric energy to the outside of the battery pack. In terms of the overall structure, the electric core includes an electric core housing 3, a pole group arranged in the electric core housing 3, and an electric core cover plate 5 for closing the electric core housing 3.

[0060] Among them, the vehicle battery pack thermal runaway detection device as described in Embodiment One is arranged in the electric core housing 3.

[0061] With the above structural arrangement, for the battery cell of this embodiment, by providing the vehicle battery pack thermal runaway detection device as described in the first embodiment in the battery cell housing 3, the thermal runaway detection of the battery cell, that is, the overall battery pack, is realized, thereby improving the safety performance of the battery pack.

[0062] Specifically based on the above overall introduction, it can be understood that the battery cell, as the component that outputs electrical energy in the battery pack, generates the most heat. And in the battery cell, since an electrochemical reaction occurs on the electrode group in the battery cell housing 3 to generate current, the electrode group generates the most heat. Therefore, the space in the battery cell housing 3 where the electrode group is arranged is the thermal environment space that is most sensitive to thermal runaway. Therefore, the vehicle battery pack thermal runaway detection device is configured in the battery cell housing 3, and the detection of the battery cell temperature, that is, the detection of the overall thermal runaway fault of the battery pack, is the most accurate and sensitive.

[0063] Since both the first contact 201 and the second contact 301 of the vehicle battery pack thermal runaway device are electrically connected to the microprocessing unit outside the battery cell, that is, the battery pack, for the convenience of connecting the vehicle battery pack thermal runaway detection device and the microprocessing unit, the mounting base 2 of this embodiment is the battery cell cover plate 5, and the vehicle battery pack thermal runaway device is arranged on the side of the battery cell cover plate 5 facing the inside of the battery cell housing 3, so as to be electrically connected to the vehicle battery pack thermal runaway detection device in the battery cell housing 3 through the battery cell cover plate 5.

[0064] The battery cell of this embodiment realizes the thermal runaway detection of the battery cell by providing the vehicle battery pack thermal runaway detection device as described in the first embodiment in the battery cell housing 3, improves the safety performance of the battery pack, and has good practicality.

[0065] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A vehicle battery pack thermal runaway detection device, characterized in that Comprising: A fixed rod, which is arranged on an installation base, and a first contact is provided on the installation base; A housing with a cavity formed inside, the housing is arranged in the thermal environment space of the battery pack and is sleeved on the fixed rod in a sliding and sealed manner; a second contact is provided outside the housing, and the connection state between the first contact and the second contact can be detected; A filler, which is filled in the housing, and the volume of the filler increases with the increase of temperature; When the housing is driven away from the installation base due to the increase in the volume of the filler, the second contact following the housing can approach and connect the first contact.

2. The vehicle battery pack thermal runaway detection device according to claim 1, wherein: A blocking portion extending radially along the fixed rod is provided on the fixed rod. When the housing is away from the installation base, the blocking portion gradually approaches and can abut against the inner wall of the top of the housing.

3. The vehicle battery pack thermal runaway detection device according to claim 1, wherein: A reset mechanism is provided between the fixed rod and the housing; When the volume of the filler decreases due to cooling, the reset mechanism drives the housing to approach the installation base.

4. The vehicle battery pack thermal runaway detection device according to claim 2, wherein: The reset mechanism is configured as an elastic member provided between the fixed rod and the housing, and the elastic member is compressed and stores energy when the housing is away from the installation base.

5. The vehicle battery pack thermal runaway detection device according to claim 4, wherein: The elastic member is a spring wound around the fixed rod.

6. The vehicle battery pack thermal runaway detection device according to any one of claims 1 to 5, wherein: The filler is paraffin.

7. The vehicle battery pack thermal runaway detection device according to claim 1, wherein: A sealing ring sleeved on the fixed rod is fixed on the housing.

8. The vehicle battery pack thermal runaway detection device according to claim 1, wherein: A channel extending axially is formed in the fixed rod, and the channel communicates with the cavity.

9. A battery cell, comprising a battery cell housing, a pole group arranged in the battery cell housing, and a battery cell cover plate for closing the battery cell housing, wherein: The vehicle battery pack thermal runaway detection device according to any one of claims 1 to 8 is arranged in the battery cell housing.

10. The battery cell according to claim 9, wherein: The installation base is the battery cell cover plate.

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