A lithium ion battery internal pressure monitoring device

Abstract

The application discloses a kind of lithium ion battery internal pressure monitoring devices, it is characterized by: including monitoring component and fixed component;The monitoring component includes the sealing ring and sensor of being arranged in battery negative electrode sequentially;The cross section of the sealing ring is the shape of 'G' character, one end is set battery negative electrode, after the other end is set sensor pressure-sensitive surface one side, pressure transition warehouse is formed on the sealing ring.The application provides a kind of lithium ion battery internal pressure monitoring device, not only can real-time monitoring the internal pressure of battery under various conditions, can be repeatedly used, and is not constrained by lithium battery structure, and measurement precision is high.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of battery performance and battery safety, and particularly relates to a lithium ion battery internal pressure monitoring device. BACKGROUND

[0002] With the wide application of lithium ion batteries in new energy vehicles, the safety performance of the lithium ion batteries attracts more and more attention. As the capacity of the lithium ion batteries is continuously improved, the residual space in the lithium ion batteries becomes smaller and smaller. Gases are generated in the lithium ion batteries in the process of storage in a high-temperature environment, overcharging, overdischarging and various abuses, the accumulation of the gases increases the internal pressure of the lithium ion batteries, and the lithium ion batteries are short-circuited or even exploded. The internal pressure of the lithium ion batteries is caused by complex factors, and is currently mainly limited by the material, manufacturing process and structure of the lithium ion batteries. Therefore, it is necessary to accurately measure the internal pressure of the lithium ion batteries to provide key data for the design of the lithium ion batteries.

[0003] There are many methods for measuring the internal pressure of the lithium ion batteries in the prior art. One method is to calculate the internal pressure of the lithium ion batteries by the deformation of the shell of the lithium ion batteries. Although this method is operable, the reliability of the method is low for the cylindrical steel shell lithium ion batteries which hardly deform. Another method is to preset a pressure-sensitive paper in the lithium ion batteries, then disassemble the lithium ion batteries, and compare the pressure-sensitive paper with a standard color card to obtain the internal pressure condition of the lithium ion batteries. This method has poor timeliness, and the swelling of the roll core in the lithium ion batteries greatly affects the test result, so the data reliability is poor. Another method is to change the structure of the lithium ion batteries and externally connect a sensor. This method increases the residual volume of the lithium ion batteries, and cannot reflect the pressure condition in the original space. Therefore, the above methods cannot meet the high-precision monitoring of the internal pressure of the lithium ion batteries. SUMMARY

[0004] In order to solve the problems of the prior art, the application provides a lithium ion battery internal pressure monitoring device, which can monitor the internal pressure of the lithium ion batteries in various conditions in real time, can be repeatedly used, is not restricted by the structure of the lithium ion batteries, and has high measurement precision.

[0005] The technical effects of the application are achieved by the following scheme.

[0006] The lithium ion battery internal pressure monitoring device in the application comprises a monitoring assembly and a fixing assembly. The monitoring assembly comprises a sealing ring and a sensor which are sequentially arranged at the negative electrode of the battery. The cross section of the sealing ring is in the shape of a Chinese character Gong, one end of the sealing ring is sleeved with the negative electrode of the battery, and the other end of the sealing ring is sleeved with one side of the pressure-sensitive surface of the sensor, and a pressure transition chamber is formed on the sealing ring.

[0007] The sealing ring is used for assembling the battery and the sensor into one body, and a pressure transition chamber is formed on the sealing ring after the sealing ring is assembled with the battery, which is used for sensing the pressure inside the battery to deform and transmit to the pressure sensing surface of the sensor, so that the measured data is more accurate; the sensor measures the pressure parameter inside the battery through the deformation of the sealing ring.

[0008] Further, the thickness of the sealing ring at the contact position between the negative electrode of the battery and the pressure sensing surface of the sensor is 0.25-0.5 mm, which can not only avoid that the contact position is too thick and the pressure inside the battery cannot make the sealing ring deform, resulting in inaccurate pressure measurement, but also avoid that the contact position is too thin and the pressure inside the battery causes the sealing ring to break and damage.

[0009] Further, the material of the sealing ring is an insulating elastic material including insulating rubber and insulating silica gel, which has good elasticity, insulation performance, heat resistance, etc.

[0010] Further, the monitoring assembly is wrapped with a sealing tape after being assembled with the battery, which is used for improving the safety performance of the battery and the monitoring assembly, and the sealing tape is a Teflon tape or a polyimide tape, which has good insulation, corrosion resistance and high temperature resistance.

[0011] Further, the fixing assembly is arranged outside the battery and the monitoring assembly, and includes a device housing, a nut and a compression ring; the device housing is a cavity structure with two open ends and a thread, and is connected with the nut near one end of the positive electrode of the battery and connected with the compression ring near the other end of the negative electrode of the battery; and an insulating wire passage is arranged on the housing of the device, in the middle of the nut and in the middle of the compression ring, which is used for arranging insulating wires to facilitate the connection between the battery and the sensor and external equipment; the device housing is used for fixing and assembling the battery, and the nut and the compression ring are used for fixing the battery and the monitoring assembly in the device housing, and the sealing between the battery and the sensor is ensured by adjusting the tightness of the nut and the compression ring; in order to ensure the sealing and stability of the connection between the nut and the device housing and the connection between the compression ring and the device housing, the nut and the device housing are connected by external threads, and the compression ring and the device housing are connected by internal threads; the pressure borne by the screw after the nut and the compression ring are locked with the device housing is greater than 60 MPa, so as to ensure the safety of the whole device; preferably, the nut and the compression ring are made of aluminum alloy or stainless steel, which has good explosion-proof performance, high temperature corrosion resistance, heat transfer, etc.

[0012] Further, the fixing assembly is arranged outside the battery and the monitoring assembly, and includes a device shell and a nut; the device shell is a cavity structure with an opening near the positive electrode end of the battery, a thread connected with the nut, and a closed end near the negative electrode end of the battery; and an insulating wire channel is arranged in the middle of the nut, the shell of the device shell, and the middle of the shell near the negative electrode end of the battery, for arranging insulating wires and facilitating the connection between the battery and the sensor and external equipment. The device shell is used for fixing and assembling the battery, and the nut is used for fixing the battery and the monitoring assembly in the device shell, and adjusting the tightness of the nut to ensure the sealing between the battery and the sensor. In order to ensure the sealing and stability of the connection between the nut and the device shell, the nut and the device shell are preferably connected by external threads; the pressure borne by the screw after the nut and the device shell are locked is greater than 60 MPa, so as to ensure the safety of the whole device; and the material of the nut and the device shell is preferably aluminum alloy or stainless steel, which has good explosion-proof performance, high-temperature corrosion resistance, and good heat transfer performance.

[0013] Further, the fixing assembly is arranged outside the battery and the monitoring assembly, and includes a device shell and a nut; the device shell is a cavity structure with an opening near the positive electrode end of the battery, a thread connected with the nut, and a closed end near the negative electrode end of the battery; and an insulating wire channel is arranged in the middle of the nut, the shell of the device shell, and the middle of the shell near the negative electrode end of the battery, for arranging insulating wires and facilitating the connection between the battery and the sensor and external equipment. The device shell is used for fixing and assembling the battery, and the nut is used for fixing the battery and the monitoring assembly in the device shell, and adjusting the tightness of the nut to ensure the sealing between the battery and the sensor. In order to ensure the sealing and stability of the connection between the nut and the device shell, the nut and the device shell are preferably connected by external threads; the pressure borne by the screw after the nut and the device shell are locked is greater than 60 MPa, so as to ensure the safety of the whole device; and the material of the nut and the device shell is preferably aluminum alloy or stainless steel, which has good explosion-proof performance, high-temperature corrosion resistance, and good heat transfer performance.

[0014] Further, an insulating washer is arranged between the nut or the device shell and the positive electrode of the battery, for insulating the battery and the nut or the device shell, and improving the safety performance of the battery; the insulating washer is made of insulating rubber or insulating silica gel, which has good elasticity, insulating performance, and heat resistance.

[0015] Further, the insulating wires for connecting the battery and the sensor to external charging and discharging equipment and electronic computers are further included. The insulating wires of the battery are connected with external charging and discharging equipment, for charging and discharging the battery; and the insulating wires of the sensor are connected with external electronic computers, for collecting pressure data on the sensor and simultaneously supplying power to the sensor.

[0016] Further, the sensor is a corrosion-resistant pressure sensor, preventing the battery from corroding the sensor due to liquid leakage; and the upper limit of the pressure test range is higher than 60MPa, ensuring that the internal pressure of the battery is within the test range of the sensor, avoiding excessive internal pressure of the battery, and the sensor cannot accurately measure.

[0017] A lithium ion battery internal pressure monitoring system, characterized in that: comprising a battery and the lithium ion battery internal pressure monitoring device, the negative electrode of the battery shell of the battery is provided with a through hole, the through hole is convenient for more truly and accurately testing the internal pressure of the battery.

[0018] Further, the position of the pressure transition chamber corresponds to the through hole, and the size is consistent with the through hole, which is 1 / 3-2 / 3 of the negative electrode area of the battery shell; the pressure transition chamber is formed after the negative electrode of the battery is assembled with the sealing ring, so it corresponds to the position of the through hole and has the same size; the size of the through hole is 1 / 3-2 / 3 of the negative electrode area of the battery shell, which can not only make the internal pressure of the battery more truly and accurately measured, but also prevent the through hole from being too large to cause the battery to leak.

[0019] The lithium ion battery internal pressure monitoring device of the application has the following advantages:

[0020] 1. The internal pressure of the battery under various conditions can be monitored in real time, and the device can be repeatedly used.

[0021] 2. Not restricted by the structure of the lithium battery, it can be a cylindrical, square or soft package battery, but is not limited to these structures, and the device can be implemented.

[0022] 3. High measurement accuracy, very close to the actual internal pressure of the battery, providing key data test scheme for safety design of battery manufacturers, and being beneficial to safety design and research of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The assembly overall structure diagram of the lithium ion battery internal pressure monitoring device (nut-device shell-pressing ring structure) in the application is shown in the figure;

[0024] Figure 2 The assembly overall structure diagram of the lithium ion battery internal pressure monitoring device (nut-device shell structure) in the application is shown in the figure;

[0025] Figure 3 The assembly overall structure diagram of the lithium ion battery internal pressure monitoring device (device shell-pressing ring structure) in the application is shown in the figure.

[0026] The reference signs are explained as follows:

[0027] 1. Battery; 101. Through hole; 2. Sealing ring; 201. Pressure transition chamber; 3. Sensor; 4. Device housing; 5. Nut; 6. Clamping ring; 7. Insulating washer. DETAILED DESCRIPTION

[0028] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0029] The internal pressure monitoring device of a lithium-ion battery in an embodiment of the present invention is as shown in the attached Figure 1 、 2 As shown in Figure 3, it includes a monitoring component and a fixing component. The monitoring component includes a sealing ring 2 and a sensor 3 which are sequentially arranged on the negative electrode of the battery. The cross section of the sealing ring is an "I" shape. One end is sleeved with the negative electrode of the battery, and the other end is sleeved with one side of the pressure-sensitive surface of the sensor, and a pressure transition chamber 201 is formed on the sealing ring.

[0030] The sealing ring integrates the battery and sensor. Once assembled, it forms a pressure transition chamber, sensing internal battery pressure and deforming to transmit this pressure to the sensor's pressure-sensing surface, enhancing accuracy. The sensor measures internal battery pressure parameters through the deformation of the sealing ring. Sensor 3 is corrosion-resistant to prevent corrosion from battery leakage. Its upper pressure test range is greater than 60 MPa, ensuring the battery's internal pressure is within the sensor's test range and preventing excessive internal pressure from preventing accurate measurement.

[0031] The thickness of the sealing ring at the point of contact between the battery's negative electrode and the sensor's pressure-sensing surface is 0.25-0.5mm. This prevents the seal from being too thick at the point of contact, preventing the internal battery pressure from deforming the seal and resulting in inaccurate pressure measurements, and from being too thin at the point of contact, preventing the internal battery pressure from causing the seal to rupture and damage. The sealing ring is made of an insulating elastic material, including insulating rubber and insulating silicone. These materials not only have excellent elasticity and insulation properties, but also excellent heat resistance. After the monitoring component is assembled with the battery, it is wrapped with sealing tape (not shown in the figure) to enhance the safety of the battery and monitoring component. The sealing tape is made of Teflon tape or polyimide tape, which is not only thin and lightweight but also has excellent insulation, corrosion resistance, and high-temperature resistance.

[0032] The fixed assembly is arranged outside the battery and the monitoring assembly, and is used for fixing and assembling the battery, and can be a nut-device shell-tight ring structure, a nut-device shell structure or a device shell-tight ring structure, and an insulating washer 7 arranged on the positive electrode of the battery is arranged between the nut 5 or the device shell 4 and the positive electrode of the battery, and is used for insulating the battery and the nut or the device shell, and improves the safety performance of the battery; the insulating washer is made of insulating rubber or insulating silica gel material, and has good elasticity, insulation performance and heat resistance. The lithium ion battery internal pressure monitoring device further comprises insulating wires (not shown in the figure) for connecting the battery and the sensor to an external charging and discharging device and an electronic computer respectively, the insulating wire of the battery is connected to the external charging and discharging device, and is used for charging and discharging the battery; and the insulating wire of the sensor is connected to the external electronic computer, and is used for collecting pressure data on the sensor and simultaneously supplying power to the sensor.

[0033] A lithium ion battery internal pressure monitoring system comprises a battery and the lithium ion battery internal pressure monitoring device, and a through hole 101 is arranged on the negative electrode of the battery shell of the battery 1, so that the pressure inside the battery can be more truly and accurately tested. The position of the pressure transition bin 201 corresponds to the through hole, and the size of the pressure transition bin is consistent with the size of the through hole, and the size of the pressure transition bin is 1 / 3-2 / 3 of the area of the negative electrode of the battery shell; the pressure transition bin is formed after the negative electrode of the battery is assembled with the sealing ring, so that the position of the pressure transition bin corresponds to the through hole, and the size of the pressure transition bin is consistent; the size of the through hole is 1 / 3-2 / 3 of the area of the negative electrode of the battery shell, so that the pressure inside the battery can be more truly and accurately measured, and the phenomenon of liquid leakage of the battery caused by the too large through hole can be prevented.

[0034] The specific implementation of the lithium ion battery internal pressure monitoring device in the embodiment of the application is as follows:

[0035] Embodiment 1:

[0036] As shown in the accompanying drawings Figure 1As shown, the fixing assembly is located outside the battery and monitoring assembly and includes a device housing 4, a nut 5, and a clamping ring 6. The device housing is a cavity structure with two open ends and a thread. The end near the positive electrode of the battery is connected to the nut, and the end near the negative electrode of the battery is connected to the clamping ring. Insulated wire channels are provided on the housing, in the middle of the nut, and in the middle of the clamping ring for installing insulated wires to facilitate the connection of the battery and sensor to external devices. The device housing is used to fix and assemble the battery, and the nut and clamping ring are used to fix the battery and monitoring assembly within the device housing. The tightness of the nut and clamping ring is adjusted to ensure the seal between the battery and sensor. In order to ensure the sealing and stability of the connection between the nut and the clamping ring and the device housing, the nut and the device housing are preferably connected with external threads, and the clamping ring and the device housing are preferably connected with internal threads; after the nut and the clamping ring are locked with the device housing, the pressure on the screws is greater than 60MPa to ensure the overall safety of the device; it is preferably made of aluminum alloy or stainless steel, which not only has good explosion-proof performance and high-temperature corrosion resistance, but also has good heat transfer properties.

[0037] Example 2:

[0038] As attached Figure 2 As shown, the fixing assembly is arranged outside the battery and monitoring assembly, including a device housing 4 and a nut 5; the device housing is a cavity structure that is open near the positive end of the battery, has a thread connected to the nut, and is closed near the negative end of the battery; and the middle part of the nut, the shell of the device housing, and the middle part of the shell near the negative end of the battery are all provided with an insulated wire channel for arranging insulated wires to facilitate the connection of the battery and sensor with external equipment. The device housing is used to fix and assemble the battery, and the nut is used to fix the battery and monitoring assembly in the device housing, and the tightness of the nut is adjusted to ensure the sealing between the battery and the sensor. In order to ensure the sealing and stability of the connection between the nut and the device housing, the nut and the device housing are preferably connected by external threads; after the nut and the device housing are locked, the pressure on the screw is greater than 60MPa to ensure the safety of the entire device; it is preferably made of aluminum alloy or stainless steel, which not only has good explosion-proof performance and high-temperature corrosion resistance, but also has good heat transfer properties.

[0039] Example 3:

[0040] As attached Figure 3As shown, the fixing assembly is arranged outside the battery and the monitoring assembly, including a device housing 4 and a compression ring 6; the device housing is a cavity structure with an opening near the negative electrode end of the battery, a thread connected with the compression ring, and a closed end near the positive electrode end of the battery; and an insulating wire passage is arranged in the middle of the compression ring, the housing of the device housing, and the middle of the housing near the positive electrode end of the battery, for arranging the insulating wire and facilitating the connection between the battery and the sensor and external equipment. The device housing is used for fixing and assembling the battery, and the compression ring is used for fixing the battery and the monitoring assembly in the device housing, and the tightness of the compression ring is adjusted to ensure the sealing between the battery and the sensor. In order to ensure the sealing and stability of the connection between the compression ring and the device housing, the compression ring and the device housing are preferably connected by internal threads; the pressure borne by the screw after the compression ring and the device housing are locked is greater than 60MPa, so as to ensure the safety of the whole device; and the material of the compression ring and the device housing is preferably aluminum alloy or stainless steel, which not only has good explosion-proof performance and high-temperature corrosion resistance, but also has good heat transfer performance.

[0041] The pressure monitoring device is placed in different states including formation and high-temperature storage, or the test battery is charged and discharged by using a charging and discharging device, and the pressure parameters in the test battery can be monitored and analyzed in real time by the electronic computer connected with the sensor. The size and specification of the test battery are consistent with those of the commercial finished battery, and the assembly process of the test battery and the temperature and humidity involved in the packaging of the pressure monitoring device meet the requirements of the process file of the same type of battery production line.

[0042] The internal pressure monitoring device of the lithium ion battery in the embodiment of the application can more truly and accurately monitor the pressure in the battery by opening a through hole in the negative electrode of the battery shell, assembling the battery negative electrode and the sealing ring, forming a pressure transition chamber on the sealing ring corresponding to the position of the through hole and having the same size, deforming the sealing ring in response to the pressure in the battery, forming a deformation pressure, and transmitting the deformation pressure to the pressure sensing surface of the sensor assembled on the other end of the sealing ring through the pressure transition chamber, so that the measured data is more accurate.

[0043] A fixing assembly is arranged outside the battery and the monitoring assembly, and is used for fixing the battery and the monitoring assembly. The device housing of the fixing assembly can be a cavity structure with two open ends or one open end and one closed end. When the device housing is a cavity structure with two open ends, the tightness of the adjusting nut and the compression ring can be adjusted to ensure the sealing between the battery and the sensor. When the device housing is a cavity structure with one open end and one closed end, the tightness of the adjusting nut or the compression ring and the device housing can be adjusted to ensure the sealing between the battery and the sensor. An insulating wire passage is arranged on the fixing assembly, and the insulating wire on the battery and the sensor can be connected with the external charging and discharging device and the electronic computer through the insulating wire passage. The charging and discharging device is used for charging and discharging the battery, and the electronic computer is used for collecting the pressure data on the sensor and simultaneously supplying power to the sensor.

[0044] In order to improve the safety of the testing device as a whole, the battery and the monitoring assembly are wrapped with an insulating and corrosion-resistant sealing tape, an insulating washer is sleeved on the positive electrode of the battery between the positive electrode and the nut, and aluminum alloy or stainless steel material with good explosion-proof performance and high-temperature corrosion resistance is used as the device shell, the nut and the compression ring, and a corrosion-resistant pressure sensor is also selected for the sensor.

[0045] As can be seen from the above embodiment, the application provides a lithium ion battery internal pressure monitoring device, which can not only monitor the internal pressure of the battery under various conditions in real time and be repeatedly used, but also is not restricted by the structure of the lithium battery and has high measurement accuracy.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the application rather than limit them, and although the embodiments of the application have been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the embodiments of the application can still be modified or replaced equivalently, and these modifications or equivalent replacements should not make the modified technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A lithium-ion battery internal pressure monitoring device, characterized in that: Includes monitoring components and fixed components; The monitoring assembly includes a sealing ring and a sensor sequentially arranged at the negative electrode of the battery; The cross section of the sealing ring is an "I" shape, one end of which is sleeved with the negative electrode of the battery, and the other end is sleeved with the pressure-sensitive surface of the sensor, forming a pressure transition chamber on the sealing ring; The thickness of the sealing ring at the contact position between the battery negative electrode and the sensor pressure sensing surface is 0.25-0.5mm; The negative electrode of the battery shell is provided with a through hole; the position of the pressure transition chamber corresponds to the through hole, and the size is consistent with the through hole, which is 1 / 3-2 / 3 of the area of ​​the negative electrode of the battery shell.

2. The lithium-ion battery internal pressure monitoring device according to claim 1, wherein: The sealing ring is made of insulating elastic material including insulating rubber and insulating silicone.

3. The lithium-ion battery internal pressure monitoring device according to claim 1, wherein: After the monitoring component is assembled with the battery, the outside is wrapped with a sealing tape, which is a Teflon tape or a polyimide tape.

4. The lithium-ion battery internal pressure monitoring device according to claim 1, wherein: The fixing assembly is arranged outside the battery and monitoring assembly, and includes a device shell, a nut and a clamping ring; the device shell is a cavity structure with openings at both ends and provided with threads, and is connected to the nut at the end close to the positive pole of the battery and connected to the clamping ring at the end close to the negative pole of the battery, and insulated wire channels are provided on the shell of the device shell, the middle of the nut and the middle of the clamping ring.

5. The lithium-ion battery internal pressure monitoring device according to claim 1, wherein: The fixing component is arranged outside the battery and monitoring component, and includes a device shell and a nut; the device shell is an open cavity structure near the positive pole of the battery, with a thread connected to the nut, and closed near the negative pole of the battery; and an insulated wire channel is provided in the middle of the nut, on the shell of the device shell, and in the middle of the shell near the negative pole of the battery.

6. The lithium-ion battery internal pressure monitoring device according to claim 4 or 5, wherein: The fixing assembly is arranged outside the battery and monitoring assembly, and includes a device shell and a clamping ring; the device shell is an open cavity structure near the negative pole of the battery, with a thread connected to the clamping ring, and closed near the positive pole of the battery; and an insulated wire channel is provided in the middle of the clamping ring, on the shell of the device shell, and in the middle of the shell near the positive pole of the battery.

7. The lithium-ion battery internal pressure monitoring device according to claim 6, wherein: An insulating washer is provided between the nut or the device shell and the positive electrode of the battery and is sleeved on the positive electrode of the battery. The insulating washer is made of insulating rubber or insulating silicone.

8. The lithium-ion battery internal pressure monitoring device according to claim 1, wherein: It also includes insulated wires for connecting the battery and the sensor to external charging and discharging equipment and an electronic computer respectively.

9. The lithium-ion battery internal pressure monitoring device according to claim 1, wherein: The sensor is a corrosion-resistant pressure sensor, and the upper limit of the pressure test range is higher than 60MPa.

10. A lithium-ion battery internal pressure monitoring system, characterized in that: The invention comprises a battery and the internal pressure monitoring device of a lithium-ion battery according to any one of claims 1 to 9.

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