Cylindrical lithium battery cell short circuit test tooling

Abstract

The utility model provides cylindrical lithium cell short circuit test frock, this test frock contains insulating base and clamping mechanism, wherein, clamping mechanism is constituted by two top screws of opposite setting, the positive and negative pole of lithium cell can respectively with two top screw piece contact and be clamped in the clamping area between two top screw pieces, compared with prior art, this test frock discarded the traditional welding or crocodile clip clamping mode, but the adjustable clamping force between top screw piece is used to reliably fix lithium cell, it can be seen, the test frock of this scheme utilizes the structural characteristics of top screw piece itself not only can effectively contact with the positive and negative pole of lithium cell, and can realize the adjustment of clamping area size through the adjustment of at least one top screw piece to adapt to various models of cylindrical lithium cell, significantly improve the reliability and universality of frock use, and then can effectively improve battery test effect, avoid the lithium cell of quality abnormality and flow to the market.

Description

Technical Field

[0001] This utility model belongs to the field of battery testing technology, and in particular relates to a short-circuit testing fixture for cylindrical lithium battery cells. Background Technology

[0002] Batteries are ubiquitous in our daily lives, used in mobile phones, laptops, power tools, electric vehicles, small household appliances, as well as streetlights, navigation lights, and backup power supplies. They provide continuous and stable power to various electronic devices. Batteries are widely used in consumer electronics, new energy vehicles, energy storage systems, and the low-altitude economy, and their applications are constantly expanding with the development of new technologies such as solid-state batteries.

[0003] As the core component of a battery, the battery cell is the energy source, responsible for the storage and release of electrical energy. It directly determines the battery's key performance characteristics such as voltage, capacity, cycle life, and safety. Therefore, battery cells undergo a series of safety certification tests before use, including short-circuit tests, forced discharge, thermal shock, heavy object impact, compression, drop tests, low pressure tests, and puncture tests, to ensure that the battery will not explode or catch fire under extreme conditions and meets safety standards.

[0004] According to the IEC 62133-2 2021 standard, which specifies the safety and testing methods for rechargeable lithium-ion batteries, a key test for battery cells is the short-circuit test. The test requirements are as follows: After the fully charged battery cell is placed in an ambient temperature of 55℃±5℃ for 1-4 hours to stabilize, the positive and negative terminals of the battery cell are short-circuited with a resistor of 80mΩ±20mΩ in the same temperature environment. The test is continued for 24 hours or the battery surface temperature drops to 20% of the maximum temperature rise, whichever comes first. The result requires that the battery cell does not catch fire or explode.

[0005] Short-circuit testing simulates a scenario where the positive and negative terminals of a battery cell are directly short-circuited. It monitors key parameters such as short-circuit current and temperature changes in real time to verify whether the battery cell can withstand a short-circuit state without causing a serious safety accident. This is crucial for ensuring the safety of the battery cell in the event of an accidental short circuit. In the existing testing process, the positive and negative terminals of the battery cell are usually soldered to the wires or clamped with alligator clips and connected in series with a short-circuit resistor for short-circuit testing. This process is cumbersome in terms of connecting, insulating, and fixing the positive and negative terminals of the battery cell to the wires. At the same time, there is a risk that the short-circuit connection circuit may break due to high temperature during the test, causing the test to be interrupted and invalid, thus reducing the efficiency and reliability of the test.

[0006] Based on the above analysis, this solution designs a short-circuit test fixture for cylindrical lithium battery cells. Utility Model Content

[0007] The purpose of this invention is to provide a cylindrical lithium battery cell short-circuit testing fixture, which has advantages such as simple structure, safety and reliability, and convenient measurement, and solves the shortcomings of existing testing in terms of low reliability and efficiency.

[0008] This solution provides a short-circuit testing fixture for a cylindrical lithium battery cell: it includes an insulating base and a clamping mechanism. The clamping mechanism comprises at least one set of clamping components fixed to the insulating base. The clamping mechanism consists of two opposing set screw components, each set screw component including a vertical rod and a lead screw. The vertical rod is fixed to the insulating base, and the lead screw is mounted above the vertical rod via a lead screw seat. An adjustable clamping area is formed between the lead screws of the two set screw components, and test cables that can communicate with the positive and negative terminals of the lithium battery are respectively connected to the lead screws of the two set screw components.

[0009] As a preferred embodiment of the application: the end of the lead screw that contacts the positive and negative terminals of the lithium battery is provided with an internal threaded hole, through which various types of copper pillars can be connected to adapt to the positive and negative terminals of the lithium battery of the corresponding size.

[0010] As a preferred embodiment of the application: the insulating base is provided with two sets of U-shaped through grooves extending along its length and arranged in parallel, and the uprights of the two set screws pass through the corresponding U-shaped through grooves and are fixed on the insulating base.

[0011] As a preferred embodiment of the application: the upright is a threaded rod, which is fixed to the insulating base by a nut.

[0012] As a preferred embodiment of the application: the test cables connected to the two set screws are connected through a short-circuit control device and can be connected in series with the lithium battery to form a test circuit. Adjusting the short-circuit control device can control the on / off state of the test circuit.

[0013] As a preferred embodiment of the application: the short-circuit control device includes a low-resistance short-circuit resistor and a control switch connected in series.

[0014] As a preferred embodiment of the application: the resistance of the low-resistance short-circuit resistor is 50mΩ or 80mΩ, and the control switch is either a relay or a contactor.

[0015] As a preferred embodiment of the application: the test cable is provided with a mounting terminal, and a locking buckle is provided on the lead screw, which can lock the mounting terminal between itself and the lead screw seat.

[0016] As a preferred embodiment of the application, it also includes a temperature testing component comprising a magnetic thermocouple, which can be connected to an external temperature display via a wire, and the magnetic thermocouple comprises, from the inside out, a thermocouple module, a heat insulation layer, and a magnet base.

[0017] Compared with existing technologies, the advantages of this application are: This test fixture includes an insulating base and a clamping mechanism. The clamping mechanism consists of two opposing set screws. The positive and negative terminals of the lithium battery can contact the two set screws respectively and be clamped in the clamping area between them. Compared with existing methods, this test fixture abandons the traditional welding or alligator clip clamping method and instead uses an adjustable clamping force between the set screws to reliably fix the lithium battery. It can be seen that this test fixture utilizes the structural characteristics of the set screws themselves to not only effectively contact the positive and negative terminals of the lithium battery, but also to adjust the size of the clamping area by adjusting at least one set screw to adapt to various types of cylindrical lithium batteries. This significantly improves the reliability and versatility of the fixture, thereby effectively improving the battery testing results and preventing substandard lithium batteries from entering the market. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the testing fixture provided by this utility model, which includes a set of clamping mechanisms.

[0019] Figure 2 This is a schematic diagram of the overall structure of the testing fixture provided by this utility model, which includes two sets of clamping mechanisms.

[0020] Figure 3 This is a diagram showing the usage status of the testing fixture provided by this utility model.

[0021] Figure 4 This is a cross-sectional structural diagram of the magnetic thermocouple provided by this utility model.

[0022] Figure Labels

[0023] 10 is the insulating base; 101 is the U-shaped through groove; 20 is the set screw; 201 is the upright; 202 is the lead screw; 203 is the lead screw seat; 204 is the copper column; 205 is the nut; 206 is the knob; 207 is the locking buckle; 300 is the test cable; 301 is the short-circuit control component; 302 is the mounting terminal; 40 is the temperature test component; 401 is the magnetic thermocouple; 4011 is the heat insulation layer; 4012 is the thermocouple module; 4013 is the magnet base; 402 is the temperature display; 403 is the wire. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be emphasized that the following description is merely exemplary and not intended to limit the scope and application of the present invention.

[0025] This embodiment provides a short-circuit testing fixture for a cylindrical lithium battery cell, comprising an insulating base 10 and a clamping mechanism. The insulating base 10 is made of polyimide resin material, possessing properties such as high temperature resistance, flame retardancy, and insulation, thus fulfilling its supporting function during testing. The clamping mechanism comprises at least one set and is fixed to the insulating base 10, such as... Figure 1 or Figure 2 The diagram shows a structural schematic of one or two sets of clamping mechanisms on the insulating base 10 provided in this embodiment. As can be seen from the diagram, when multiple sets are provided, the clamping mechanisms are arranged at certain intervals along the length of the insulating base 10. Each clamping mechanism consists of two opposing set screw members 20. Each set screw member 20 includes a vertical rod 201 and a lead screw 202. The vertical rod 201 is fixed to the insulating base 10, and the lead screw 202 is mounted above the vertical rod 201 via a lead screw seat 203. It is understood that the lead screw seat 203 should have a threaded hole for the set screw. The screw thread passes through the threaded hole and connects to the lead screw seat 203, allowing it to reciprocate relative to the lead screw seat 203. An adjustable clamping area is formed between the lead screws 202 of the two set screws 20, and test cables 300 that can communicate with the positive and negative terminals of the lithium battery are respectively connected to the lead screws 202 of the two set screws 20. Understandably, within the clamping area, the ends of the two set screws should respectively connect to the positive and negative terminals of the cylindrical lithium battery. In this embodiment, the set screw 20 is made of copper, which has good conductivity and mechanical strength, meeting the requirements of this embodiment.

[0026] In this embodiment, when the clamping mechanism comprises multiple sets, such as... Figure 2 When two sets are included, the two sets of clamping mechanisms are installed on the insulating base 10 at a certain distance, and a test cable 300 is connected to the lead screw 202 of each of the two adjacent clamping mechanisms. This can avoid mutual interference when the two adjacent clamping mechanisms perform lithium battery tests simultaneously.

[0027] As a preferred embodiment, the end of the lead screw 202 that contacts the positive and negative terminals of the lithium battery is provided with an internal threaded hole. Various types of copper pillars 204 can be connected through this internal threaded hole to adapt to the positive and negative terminals of the lithium battery of the corresponding size. That is, in order to improve the reliability of the contact between the lead screw 202 and the lithium battery, this embodiment can select and replace the copper pillar 204 of an appropriate size according to the cylindrical lithium battery model. It is understood that the copper pillar 204 should be a conventional existing structure. Therefore, the structure of the copper pillar 204 will not be described in detail in this embodiment.

[0028] As a preferred embodiment, the insulating base 10 is provided with two sets of U-shaped through grooves 101 extending along its length and arranged in parallel. The uprights 201 of the two set screws 20 pass through the corresponding U-shaped through grooves 101 and are fixed on the insulating base 10. In this embodiment, by setting the U-shaped through grooves 101, it is convenient to adjust the distance between two adjacent set screws 20, providing conditions for subsequent testing. It can be understood that the length of the U-shaped through groove 101 can be determined by the number of set screws 20 that need to be arranged, and the width can be determined according to the diameter of the upright. In this embodiment, the upright 201 is preferably a threaded rod, which can pass through the U-shaped through groove 101 and be fixed on the insulating base 10 by a nut 205.

[0029] The test cables 300, which are respectively connected to the two set screws 20, are connected through a short-circuit control element 301 and can be connected in series with the lithium battery to form a test circuit. Adjusting the short-circuit control element 301 can control the on / off state of the test circuit. Figure 3 As shown in the figure, for ease of testing, in this embodiment, a short-circuit control element 301 is connected to the test cables 300 of the two opposing lead screws 202 of a clamping mechanism. The short-circuit control element 301 connects the two test cables 300. After the clamping mechanism completes clamping the cylindrical lithium battery, the two test cables 300 connected by the short-circuit control element 301 can be connected in series with the lithium battery to form a test circuit. The on / off state of this test circuit is controlled by the short-circuit control element 301. In this embodiment, according to the lithium battery short-circuit test requirements, the short-circuit control element 301 includes a low-resistance short-circuit resistor and a control switch connected in series. In this embodiment, the resistance of the low-resistance short-circuit resistor is 50mΩ or 80mΩ, and the control switch is either a relay or a contactor. In this embodiment, the resistance of the low-resistance short-circuit resistor is preferably 80mΩ, and the control switch is a contactor. It can be seen that this embodiment achieves the integrated design of the test equipment by connecting the short-circuit control component 301 between the two test cables 300. There is no need to connect an external short-circuit resistor during the test, which improves the installation efficiency of the test circuit and the reliability of the test circuit connection, providing a foundation for subsequent effective testing. In addition, the use of a contactor as a control switch can realize remote control of the test circuit.

[0030] As a preferred embodiment, the test cable 300 is provided with a mounting terminal 302. In this embodiment, the mounting terminal 302 is preferably a U-shaped buckle. At the same time, a locking buckle 207 is provided on the lead screw 202. In this embodiment, the locking buckle 207 is preferably a wing nut. The mounting terminal 302, i.e. the U-shaped buckle, can be locked between the locking buckle 207 and the lead screw seat 203. In use, the U-shaped buckle is inserted into the lead screw 202, and then the wing nut is rotated until the wing nut abuts against the U-shaped buckle and makes tight contact with the lead screw seat 203. This design realizes the detachable installation of the test cable 300 and the set screw, improving the convenience of using the test fixture.

[0031] Currently, during testing, the short-circuit condition of the lithium battery is measured by real-time monitoring of key parameters such as short-circuit current and temperature changes. Furthermore, since cylindrical lithium batteries typically have metal casings, this embodiment of the testing fixture also includes a temperature testing component 40. Figure 3 As shown, the temperature testing component 40 includes a magnetic thermocouple 401, specifically a magnetic K-type thermocouple. The magnetic thermocouple 401 can be connected to an external temperature display 402 via a wire 403. The magnetic thermocouple 401, from the inside out, includes a thermocouple module 4012, a heat insulation layer 4011, and a magnet base 4013. Figure 4 As shown, in this embodiment, the heat insulation layer 4011 can specifically be made of mica sheet. The mica sheet can prevent local overheating and lay the foundation for accurate thermocouple measurement. The thermocouple module 4012 can be made of micro-film thermocouple. The thickness of the micro-film thermocouple is 0.1mm and the response time is 20ms. At the same time, the flexible structure is easy to fit with the curved surface of the cylindrical lithium battery, which meets the requirements of this embodiment. In addition, multiple micro-film thermocouples can be arranged and placed between the heat insulation layer 4011 and the magnet base. In use, the magnetic thermocouple 401 can be connected to the external temperature display 402 and then attached to the surface of the cylindrical lithium battery. When the test circuit is connected, the surface temperature of the battery can be measured in real time.

[0032] Understandably, to ensure the accuracy of the test, an external short-circuit current testing tool can be used as needed during actual testing. The short-circuit current on the test cable 300 is obtained through this short-circuit current testing tool, and then the short-circuit test result of the lithium battery is judged in combination with the temperature obtained by the magnetic thermocouple 401. In this embodiment, the short-circuit current testing tool is preferably the conventional clamp meter.

[0033] The test steps in this embodiment include: (1) First, place multiple (preferably 5, and test each one) fully charged cylindrical lithium battery samples in an environmental chamber at 55℃±5℃ for 1h-4h to stabilize them; (2) Then place the test fixture in an environmental chamber; (3) Adjust the size of the clamping area by using the knob 206 at the end of the lead screw 202 so that the positive and negative terminals of the cylindrical lithium battery are in close contact with the copper pillars 204 of the two lead screws 202 respectively and clamped and fixed. Then rotate the wing nut 205 to fix the test cable 300 on the lead screw 202. Relying on the stable clamping force and excellent conductivity of the lead screw 202, the positive and negative terminals of the battery cell are connected to the short circuit control component 301 (including an 80mΩ low resistance short circuit resistor and a relay) through the test cable 300. (4) At least one magnetic thermocouple 401 is placed on the surface of the cylindrical lithium battery to detect the temperature of the cell surface during the short circuit test. The magnetic thermocouple 401 is connected to an external temperature display 402 through a wire 403. (5) Clamp the clamp meter onto a test cable 300 to monitor the short-circuit current in the test circuit; (6) Control the contactor in the short-circuit control component 301 to engage, so that the test cable 300 and the 80mΩ short-circuit resistance are fully connected to form a test circuit, thereby achieving the purpose of short-circuit testing of the positive and negative poles of the battery cell. (7) Observe the short circuit test phenomenon of the battery cell, record the test results of the ammeter and temperature display 402, and judge the short circuit situation based on the test results.

[0034] In summary, the test fixture of this embodiment utilizes the structural characteristics of the set screw 20 to not only effectively contact the positive and negative electrodes of the lithium battery, but also allows for adjustment of the clamping area size by adjusting at least one set screw 20 to accommodate various types of cylindrical lithium batteries. Almost all cylindrical lithium batteries can be mounted and fixed on this test fixture for short-circuit testing, significantly improving the reliability and versatility of the fixture. Furthermore, the combination of the magnetic thermocouple 401 and the short-circuit control component 301 enhances testing convenience, eliminating the need for numerous external devices. Therefore, the test fixture of this embodiment possesses advantages such as simple structure, safety and reliability, and convenient measurement, overcoming the shortcomings of low reliability and efficiency in existing tests. It can effectively improve battery testing results and prevent substandard lithium batteries from entering the market.

[0035] The above descriptions are merely embodiments of this utility model, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various improvements without departing from this utility model, and these improvements should also be considered within the scope of protection of this utility model. These improvements will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of the claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A short-circuit testing fixture for cylindrical lithium battery cells, characterized in that: The device includes an insulating base (10) and a clamping mechanism. The clamping mechanism comprises at least one set and is fixed on the insulating base (10). The clamping mechanism consists of two opposing set screws (20). Each set screw (20) includes a vertical rod (201) and a lead screw (202). The vertical rod (201) is fixed on the insulating base (10). The lead screw (202) is mounted above the vertical rod (201) via a lead screw seat (203). An adjustable clamping area is formed between the lead screws (202) of the two set screws (20). Test cables (300) that can communicate with the positive and negative terminals of a lithium battery are respectively connected to the lead screws (202) of the two set screws (20).

2. The cylindrical lithium battery cell short-circuit test fixture according to claim 1, characterized in that: The lead screw (202) has an internal threaded hole at one end that contacts the positive and negative electrodes of the lithium battery. Various types of copper pillars (204) can be connected through the internal threaded hole to adapt to the positive and negative electrodes of the lithium battery of the corresponding size.

3. The short-circuit test fixture for cylindrical lithium battery cells according to claim 1, characterized in that: The insulating base (10) is provided with two sets of U-shaped through grooves (101) extending along its length and arranged in parallel. The uprights (201) of the two set screws (20) pass through the corresponding U-shaped through grooves (101) and are fixed on the insulating base (10).

4. The short-circuit test fixture for cylindrical lithium battery cells according to claim 1, characterized in that: The upright (201) is a threaded rod, which is fixed to the insulating base (10) by a nut (205).

5. The short-circuit test fixture for cylindrical lithium battery cells according to claim 1, characterized in that: The test cable (300) connected to the two set screws (20) respectively is connected through a short-circuit control (301) and can be connected in series with the lithium battery to form a test circuit. Adjusting the short-circuit control (301) can control the on / off state of the test circuit.

6. The short-circuit test fixture for cylindrical lithium battery cells according to claim 5, characterized in that: The short-circuit control unit (301) includes a low-resistance short-circuit resistor and a control switch connected in series.

7. The short-circuit test fixture for cylindrical lithium battery cells according to claim 6, characterized in that: The resistance of the low-resistance short-circuit resistor is 50mΩ or 80mΩ, and the control switch is either a relay or a contactor.

8. The short-circuit test fixture for cylindrical lithium battery cells according to claim 1, characterized in that: The test cable (300) is provided with a mounting terminal (302), and a locking buckle (207) is provided on the lead screw (202). The mounting terminal (302) can be locked between itself and the lead screw seat (203) by the locking buckle (207).

9. The short-circuit test fixture for cylindrical lithium battery cells according to claim 1, characterized in that: It also includes a temperature testing component, which includes a magnetic thermocouple that can be connected to an external temperature display via wires. The magnetic thermocouple consists of a thermocouple module, a heat insulation layer, and a magnet base from the inside out.

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