Device and method for measuring current change after thermal runaway of battery module

Abstract

The invention relates to the technical field of batteries, and discloses a device and method for measuring current change after thermal runaway of a battery module, and the device comprises a battery cell clamp which is provided with a plurality of groups of clamping plates which are clamped on the large surfaces of the two sides of a battery cell, a clamping space for clamping a single battery cell is formed between the two clamping plates in each group, and the multiple groups of clamping plates are arranged at intervals; the electric connecting piece is used for electrically connecting the battery cells in the plurality of clamping spaces; according to the invention, each battery cell is separately arranged in one clamping space, after thermal runaway is carried out on the single battery cell, the influence on other battery cells can be reduced, and the Hall sensor is connected to the electric connecting piece, so that the magnitude and flow direction data of current in the parallel battery cells can be acquired in real time; and the influence of the thermal runaway battery cell on other non-runaway battery cells after thermal runaway can be researched.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a device and method for measuring current changes after thermal runaway of a battery module. Background Art

[0002] As the country attaches more importance to automobile safety, the requirements for battery thermal runaway are becoming more and more stringent. In order to reduce R&D costs and identify the risks of various situations of thermal runaway, it is necessary to increase research on various application scenarios of thermal runaway.

[0003] In parallel cells, the voltage of each cell is consistent. Once a single cell has thermal runaway, the thermal runaway cell is shorted internally, which is equivalent to a wire with very low resistance. At this time, it is shorted externally to other normal cells. The voltage of normal cells will basically not change at the moment of thermal runaway. At this time, there is a large current between the normal cell and the thermal runaway cell. If the internal resistance of the thermal runaway cell does not change, the large current will always exist in the cell body. These large currents are one of the inducing factors for thermal runaway of the non-thermal runaway cell.

[0004] In the prior art, there is no research on the effect of the magnitude and duration of current "recharge" on the multi-parallel structure module after thermal runaway of a single cell of the multi-parallel structure module of a power battery. Summary of the invention

[0005] In view of this, the present invention provides a device and method for measuring current changes after thermal runaway of a battery module, so as to solve the problem of how to study the impact of current "recharge" on multiple parallel modules after thermal runaway of a single battery cell.

[0006] In a first aspect, the present invention provides a device for measuring current change after thermal runaway of a battery module, comprising: A battery cell clamp, comprising a plurality of groups of clamping plates for clamping on the large surfaces of both sides of the battery cell, a clamping space for clamping a single battery cell is formed between two of the clamping plates in each group, and the plurality of groups of clamping plates are arranged at intervals; An electrical connector, used to electrically connect the multiple battery cells in the clamping space; A Hall sensor is connected to the electrical connection piece.

[0007] The above technical solution of the present invention has the following advantages: each battery cell is separately arranged in a clamping space, and when a single battery cell is in thermal runaway, the impact on other battery cells can be reduced. By connecting a Hall sensor to the electrical connector, the size and flow direction data of the current in the parallel battery cells can be collected in real time, which is conducive to studying the impact of the thermal runaway battery cell on other non-runaway battery cells after thermal runaway occurs.

[0008] Optionally, the bottom of the battery cell is retracted upward into the clamping space between the two clamping plates. Through this arrangement, the bottom of the battery cell is off the ground, which can ensure that the heat loss after thermal runaway is minimized and ensure the accuracy of the temperature sensing data collected.

[0009] Optionally, the bottom of the battery cell is retracted upward into the clamping space by a distance greater than or equal to 20 mm. This arrangement can ensure that the heat loss after thermal runaway is minimized and the accuracy of the temperature sensing data collected is ensured.

[0010] Optionally, the parallel distance between two adjacent clamping spaces is greater than 50 mm. Through this arrangement, the heat generated by the thermal runaway cell is isolated from causing thermal runaway of other cells, and only the influence of the electrical factor on thermal runaway is considered.

[0011] Optionally, the parallel distance between two adjacent clamping spaces is between 50 mm and 100 mm.

[0012] Optionally, the parallel distance between two adjacent clamping spaces is greater than 100 mm.

[0013] Optionally, aerogel is arranged between the clamping plate and the large surface of the battery cell; through this arrangement, it is possible to ensure that the heat loss after thermal runaway is minimized and ensure the accuracy of temperature sensing data collection.

[0014] Optionally, the clamping plates on both sides of the battery cell are connected by fasteners; this arrangement facilitates installation and removal of the clamping plates on both sides of the battery cell.

[0015] Optionally, the electrical connector includes a copper bar, and the surface of the copper bar is covered with an insulating protective layer. This arrangement can prevent the thermal runaway charged particle ejecta from falling on the copper bar and causing sparks.

[0016] Optionally, a plurality of through holes for passing the fasteners are arranged around the clamping plate, and the fasteners include screw members passing through the through holes and locking nuts threadedly connected to both ends of the screw members.

[0017] In a second aspect, the present invention further provides a method for measuring current changes after thermal runaway of a battery module, using the device for measuring current changes after thermal runaway of a battery module described in any one of the above schemes, comprising the following steps: Clamping a plurality of battery cells in the clamping space of the battery cell clamp respectively, and charging each battery cell; Thermal runaway of a single battery cell; The Hall sensor detects the current size and direction data.

[0018] The above technical scheme of the present invention has the following advantages: first, since the device for measuring the current change after thermal runaway of the battery module described in any one of the above schemes is adopted, it has all its advantages; second, since the Hall sensor is used to detect the current size and flow direction data, it is possible to study the problem of the impact of current "reinjection" on multi-parallel modules after thermal runaway of a single battery cell.

[0019] Optionally, when charging the battery cells, each battery cell is charged individually; First, charge the battery to 4.15V with a 1C constant current and let it stand for 1 minute. Then use 0.5C constant current to charge to 4.20V and let it stand for 1min; Then use 0.25C constant current to charge to 4.28V and let it stand for 1 minute; Finally, the battery was charged to 4.35V using a 0.1C constant current and allowed to stand for 30 minutes.

[0020] Through the above settings, it can be ensured that each battery cell can be fully charged to ensure the accuracy of the experiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 A three-dimensional diagram of a device for measuring current changes after thermal runaway of a battery module according to an embodiment of the present invention; Figure 2 for Figure 1 Exploded view of a single clamping space structure; Figure 3 for Figure 2 A three-dimensional diagram of the heating structure; Figure 4 for Figure 1 A three-dimensional diagram of the Hall sensor; Figure 5 for Figure 1 A perspective view of the first electrical connector Figure 6 for Figure 1 A perspective view of the second electrical connector; Figure 7 for Figure 1 A three-dimensional view of the third electrical connector.

[0023] Description of reference numerals: 1. Clamping plate; 2. Battery cell; 3. First electrical connector; 4. Second electrical connector; 5. Third electrical connector; 6. Hall sensor; 7. Aerogel; 8. Fastener; 9. Heating structure; 10. Insulating protective layer. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0025] Combine the following Figures 1 to 7 , describing an embodiment of the present invention.

[0026] like Figure 1 As shown, a specific implementation of the device for measuring current changes after thermal runaway of a battery module provided in this embodiment includes: a battery cell clamp, an electrical connector and a Hall sensor 6, wherein the battery cell clamp has multiple groups of clamping plates 1 for clamping on the large surfaces on both sides of the battery cell 2, and a clamping space for clamping a single battery cell 2 is formed between two of the clamping plates 1 in each group, and the multiple groups of clamping plates 1 are arranged at intervals; the electrical connector is used to electrically connect multiple battery cells 2 in the clamping space, and the Hall sensor 6 is connected to the electrical connector.

[0027] In the device for measuring the current change after thermal runaway of a battery module provided in this embodiment, each battery cell 2 is separately arranged in a clamping space. When a single battery cell 2 is thermally runaway, the impact on other battery cells 2 can be reduced. By connecting a Hall sensor 6 to the electrical connector, the size and flow direction data of the current in the parallel battery cells 2 can be collected in real time, which is conducive to studying the impact of the thermal runaway battery cell 2 on other non-runaway battery cells 2 after thermal runaway occurs.

[0028] like Figure 2 As shown, in one embodiment, the bottom of the battery cell 2 is retracted upward into the clamping space between the two clamping plates 1. This arrangement keeps the bottom of the battery cell 2 away from the ground, which can ensure that the amount of heat loss after thermal runaway is minimized and the accuracy of the temperature sensing data collected is ensured. Specifically, since the bottom of the battery cell 2 is retracted upward compared to the bottom of the clamping plate 1, the bottom of the clamping plate 1 supports the ground when placed, thereby ensuring that a certain distance is maintained between the battery cell 2 and the ground, thereby preventing the heat of the battery cell 2 from being dissipated through the ground, thereby ensuring that the amount of heat loss after thermal runaway is minimized. Of course, the above description is not restrictive. In some alternative embodiments, the bottom of the battery cell 2 may be flush with the bottom of the clamping plate 1.

[0029] like Figure 2 As shown, in one embodiment, the bottom of the battery cell 2 is retracted upward into the clamping space by a distance greater than or equal to 20 mm. This retracted distance can achieve the purpose of reducing the amount of heat loss after thermal runaway of the battery cell 2. For example, in a specific embodiment, the length of the clamping plate 1 is 180 mm, the height is 117 mm, and the thickness is 20 mm. The bottom of the battery cell 2 is retracted upward into the clamping plate 1 by 20 mm, which can prevent the heat after thermal runaway from being absorbed by the ground, thereby maximizing the accuracy of the temperature sensing data collected. When the battery cell 2 is designed to be 50 mm away from the ground, it can ensure that the amount of heat loss after thermal runaway is minimized, ensuring the accuracy of the temperature sensing data collected.

[0030] like Figure 1 As shown, in one embodiment, the parallel distance between two adjacent clamping spaces is greater than 50 mm. Through this setting, the heat generation of the thermal runaway battery cell 2 is isolated from causing thermal runaway of other battery cells 2, and only the electrical effect on thermal runaway is considered. Specifically, since a certain parallel distance is maintained between two adjacent clamping spaces, when a battery cell 2 has thermal runaway, its heat generation will not affect other battery cells 2 or will have a small impact.

[0031] For example, in a specific embodiment, the parallel distance between two adjacent clamping spaces is between 50 mm and 100 mm. The setting of the parallel distance can ensure that when a battery cell 2 has thermal runaway, other battery cells 2 will have less impact.

[0032] For example, in a specific embodiment, the parallel distance between two adjacent clamping spaces is greater than 100 mm. The setting of the parallel distance can ensure that when a battery cell 2 has thermal runaway, other battery cells 2 will have less impact.

[0033] like Figure 2 As shown, in one embodiment, an aerogel 7 is arranged between the clamping plate 1 and the large surface of the battery cell 2; through this arrangement, it is possible to ensure that the heat loss after thermal runaway is minimized and the accuracy of the temperature sensing data is ensured. For example, in some specific embodiments, the thickness of the aerogel 7 is 4mm. The length and width of the aerogel 7 match the large surface size of the battery cell 2. For example, in some specific embodiments, the capacity of the battery cell 2 is 55Ah, and the length, width, and height are 26.7mm*148.4mm*97mm respectively. The full-charge voltage is 3.33V, and the working voltage is 2.8V-4.25V. A piece of aerogel 7 with a length of 148.4mm, a width of 97mm, and a thickness of 4mm is placed on the two major surfaces of the battery cell 2 to isolate the heat dissipation between the battery cell 2 and the fixture after thermal runaway.

[0034] like Figure 2 As shown, in one embodiment, the clamping plates 1 on both sides of the battery cell 2 are connected by fasteners 8; this arrangement facilitates the installation and removal of the clamping plates 1 on both sides of the battery cell 2. For example, in some specific embodiments, four 10 mm holes are opened at 8 mm positions on the four corners of the edge of the clamping plate 1 for passing the fasteners 8. The fasteners 8 include a screw member passing through the through hole and locking nuts threadedly connected to both ends of the screw member.

[0035] like Figure 2 , Figure 3 As shown, in one embodiment, a heating structure 9 is provided in a clamping space. The heating structure 9 may be a heating plate. The heating plate is attached to a large surface of the battery cell 2 and is used to perform thermal runaway control on the single battery cell 2 .

[0036] like Figure 4 As shown, in one embodiment, the Hall sensor 6 includes a main body, the main body has a through hole for passing the electrical connector, the main body is connected with a collection line, the collection line is connected to the controller, the Hall sensor 6 adopts CAN communication, and is connected to the computer through the collection line to collect data in real time, so as to monitor the size and flow direction of the current in the electrical connector in real time.

[0037] like Figure 1 As shown, in one embodiment, the electrical connector includes: a first electrical connector 3, a second electrical connector 4 and a third electrical connector 5, wherein the first electrical connector 3 includes an aluminum bar, the second electrical connector 4 includes a copper bar, and the third electrical connector 5 includes an electrical connection screw. The first electrical connector 3 is connected to the tab of the battery cell 2 by laser welding, the second electrical connector 4 connects the first electrical connector 3 between two adjacent clamping spaces, and the first electrical connector 3 and the second electrical connector 4 are connected by the third electrical connector 5.

[0038] like Figure 5 As shown, in one embodiment, the first electrical connector 3 is a U-shaped part, the width of the first electrical connector 3 is 20-40mm, which can be changed according to the overcurrent and charging and discharging strategy of the battery cell 2, and the thickness is 1mm. The two sides of the first electrical connector 3 have hole structures for passing screws. The first electrical connector 3 is arranged with a voltage acquisition line and a temperature acquisition line. The temperature of a single battery cell 2 is monitored in real time through the temperature acquisition line, and the voltage is collected in real time through the voltage acquisition line. The internal resistance of the battery cell 2 is detected by a voltage internal resistance tester, so as to monitor the change of the internal resistance of a single battery cell 2 after thermal runaway in real time.

[0039] like Figure 6As shown, in one embodiment, the surface of the copper bar of the second electrical connector 4 is covered with an insulating protective layer 10. This arrangement can prevent the sparking phenomenon caused by the thermal runaway charged particle ejection falling on the copper bar. Specifically, the insulating protective layer 10 can be an insulating tape wrapped around the surface of the soft copper bar, and the resistance of the soft copper bar does not exceed 0.08mΩ.

[0040] like Figure 7 As shown, in one embodiment, the third electrical connector 5 includes a sub-connector and a female connector that are threadedly connected to each other. The sub-connector and the female connector pass through the hole structure from both ends of the hole structure respectively, and then are connected with a threaded structure, so that the first electrical connector 3 and the second electrical connector 4 are fastened and electrically connected.

[0041] An embodiment of the present invention further provides a method for measuring current changes after thermal runaway of a battery module, using the device for measuring current changes after thermal runaway of a battery module described in the above scheme, comprising the following steps: Clamping a plurality of battery cells 2 in the clamping space of the battery cell clamp respectively, and charging each battery cell 2; Conduct thermal runaway control on a single battery cell 2; The magnitude and direction of the current are detected by the Hall sensor 6 .

[0042] The above technical solution of the present invention uses the Hall sensor 6 to detect the magnitude and flow direction of the current, and can study the problem of the impact of the current "recharge" on the multi-parallel module after the single battery cell 2 is thermally runaway. Specifically, the above technical solution utilizes the characteristic that the voltage of the multi-parallel battery cells 2 is the same. When the battery cell 2 is thermally runaway, it will be short-circuited internally, and there will be a voltage difference between the battery cells 2, resulting in a large current in the multi-parallel battery cells 2; through the above device for measuring the current change after the thermal runaway of the battery module, its current and internal resistance changes can be monitored in real time.

[0043] In one embodiment, when charging the battery cells 2, each battery cell 2 is charged individually; First, charge the battery to 4.15V with a 1C constant current and let it stand for 1 minute. Then use 0.5C constant current to charge to 4.20V and let it stand for 1min; Then use 0.25C constant current to charge to 4.28V and let it stand for 1 minute; Finally, the battery was charged to 4.35V using a 0.1C constant current and allowed to stand for 30 minutes.

[0044] Through the above arrangement, it can be ensured that each battery cell 2 can be fully charged to ensure the accuracy of the experiment.

[0045] It should be noted that the above 1C = nominal capacity 2000 mAh / h. For example, when the battery capacity is 2400 mAh, 1 C = 2.4A.

[0046] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations shall all fall within the protection scope of the present invention.

Claims

1. A device for measuring current changes after thermal runaway of a battery module, characterized in that: include: A battery cell clamp, comprising a plurality of groups of clamping plates (1) for clamping on the large surfaces on both sides of a battery cell (2), a clamping space for clamping a single battery cell (2) is formed between two of the clamping plates (1) in each group, and the plurality of groups of clamping plates (1) are arranged at intervals; An electrical connector, used for electrically connecting a plurality of battery cells (2) within the clamping space; A Hall sensor (6) is connected to the electrical connection piece.

2. The device for measuring current change after thermal runaway of a battery module according to claim 1, characterized in that: The bottom of the battery core (2) is retracted upward into the clamping space between the two clamping plates (1).

3. The device for measuring current change after thermal runaway of a battery module according to claim 2, characterized in that: The bottom of the battery cell (2) is retracted upwards into the clamping space by a distance greater than or equal to 20 mm.

4. The device for measuring current change after thermal runaway of a battery module according to claim 1, characterized in that: The parallel distance between two adjacent clamping spaces is greater than 50 mm.

5. The device for measuring current change after thermal runaway of a battery module according to claim 4, characterized in that: The parallel distance between two adjacent clamping spaces is between 50 mm and 100 mm.

6. The device for measuring current change after thermal runaway of a battery module according to claim 4, characterized in that: The parallel distance between two adjacent clamping spaces is greater than 100 mm.

7. The device for measuring current change after thermal runaway of a battery module according to any one of claims 1 to 6, characterized in that: An aerogel (7) is arranged between the clamping plate (1) and the large surface of the battery cell (2); The clamping plates (1) on both sides of the battery core (2) are connected via fasteners (8); The electrical connector comprises a copper busbar, the surface of which is covered with an insulating protective layer (10).

8. The device for measuring current change after thermal runaway of a battery module according to claim 7, characterized in that: A plurality of through holes for passing the fasteners (8) are arranged around the clamping plate (1), and the fasteners (8) comprise screw rods passing through the through holes and locking nuts threadedly connected to both ends of the screw rods.

9. A method for measuring current changes after thermal runaway of a battery module, characterized in that: The device for measuring the current change after thermal runaway of a battery module according to any one of claims 1 to 8 comprises the following steps: Clamping a plurality of battery cells (2) in the clamping space of a battery cell clamp respectively, and charging each battery cell (2); Conducting thermal runaway control on a single battery cell (2); The magnitude and direction of the current are detected by the Hall sensor (6).

10. The method for measuring current change after thermal runaway of a battery module according to claim 9, characterized in that: When charging the battery cells (2), each battery cell (2) is charged individually: First, charge the battery to 4.15V with a 1C constant current and let it stand for 1 minute. Then use 0.5C constant current to charge to 4.20V and let it stand for 1min; Then use 0.25C constant current to charge to 4.28V and let it stand for 1 minute; Finally, the battery was charged to 4.35V using a 0.1C constant current and allowed to stand for 30 minutes.

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