Device and method for detecting influence of foreign matters on battery

Abstract

The invention relates to a device and method for detecting influence of foreign matters on a battery, and the device comprises a test operation box which comprises a box body and a box cover movably connected with the box body, and the inner box bottom of the test operation box is provided with a placement table which is used for bearing a to-be-tested battery cell; the extrusion plate is movably arranged on the inner wall of the box cover, and a pressure sensor is arranged on the extrusion plate; the driving end of the extrusion driving device penetrates through the box cover and is connected with the extrusion plate, and the extrusion driving device is used for driving the extrusion plate to extrude the battery cell to be tested. The test operation box is a transparent operation box, a tester can observe the condition in the box in real time in the test process, the device is simple and easy to operate, the battery test period is short, different metal particles or nonmetal particles with different particle sizes can be tested, and the test efficiency is high. And subsequent processes such as assembly and formation of the battery cell in the prior art are not needed, so that the test cost is low.

Description

Technical Field

[0001] The present invention relates to a device and method for detecting the influence of foreign objects on a battery, belonging to the technical field of lithium-ion battery safety testing. Background Art

[0002] Due to the characteristics of high energy density, no memory effect, long single-cell cycle life, high efficiency, cleanliness and no pollution of lithium batteries, they have been widely used. Metal foreign objects will be introduced during the production process of lithium batteries. The particle sizes of metal foreign objects have different effects on the safe use of the battery. It is impossible to completely eliminate metal foreign objects during the production process. Therefore, it is very necessary to use experimental methods to determine the influence brought by metal foreign objects of different particle sizes, and then formulate standards for the particle sizes of foreign objects based on the experimental results, so as to conduct corresponding control during incoming materials and the production process; the current mainstream test and verification method is to place metal foreign objects between the electrodes of the stack before assembling the test battery stack, and then perform subsequent process steps such as assembly and formation to finally complete the production of the test battery; however, this mainstream method has the following deficiencies: 1. The cycle for producing test batteries is very long and relatively dangerous; 2. If it is necessary to compare metal foreign objects with different particle sizes and different styles, the number of test batteries is large and the test cost is very high; 3. The test process is difficult to control and the test observability is not strong. Summary of the Invention

[0003] In view of the above technical problems, the present invention provides a device and method for detecting the influence of foreign objects on a battery. This device and test method can intuitively and accurately judge the influence of foreign object particles of different particle sizes on the battery electrodes in different SOC states under different pressures. Thus, through experimental data, the particle size and content of foreign objects in the production process and incoming materials can be controlled.

[0004] To achieve the above object, the present invention adopts the following technical solutions: A device for detecting the influence of foreign objects on a battery, comprising: A test operation box, the test operation box includes a box body and a box cover movably connected to the box body. A placement table is provided on the inner bottom of the test operation box, and the placement table is used to carry the battery cell to be tested; A pressing plate, movably arranged on the inner wall of the box cover, and a pressure sensor is arranged on the pressing plate; A pressing driving device, the driving end of the pressing driving device penetrates the box cover and is connected to the pressing plate, and is used to drive the pressing plate to press the battery cell to be tested.

[0005] The test operation box of the present invention is a transparent operation box. During the test, the tester can observe the situation inside the box in real time. Moreover, the device of the present invention is simple and easy to operate, the test battery cycle is short, and it can test different particle sizes, different metal particles or non-metal particles, without the need for subsequent processes such as assembling and forming the battery cell as in the prior art. The test cost is low and the process is easy to control.

[0006] The device for detecting the influence of foreign objects on the battery preferably further includes an air extraction and ventilation device, which is arranged on the side wall of the test operation box.

[0007] The device for detecting the influence of foreign objects on the battery preferably further has a foreign object storage box arranged on the inner bottom of the test operation box.

[0008] The device for detecting the influence of foreign objects on the battery preferably has the foreign object storage box including a metal particle placement box and a non-metal particle placement box.

[0009] The device for detecting the influence of foreign objects on the battery preferably has the foreign object storage box further including a spare placement box.

[0010] The device for detecting the influence of foreign objects on the battery preferably has the box cover including a left box cover and a right box cover which are separately arranged.

[0011] The device for detecting the influence of foreign objects on the battery preferably has the left box cover and the right box cover both provided with handles.

[0012] The second aspect of the present invention provides a test method for detecting the influence of foreign objects on the battery, including the following steps: Place the test operation box on the working platform of the battery cell disassembly test laboratory; According to the requirements of different DOE tests, prepare metal foreign object particles with different particle sizes, and place non-metal foreign object particles in the foreign object storage box for standby; Disassemble the batteries in different SOC states, and take out some positive and negative electrode plates therefrom for standby; In the test session, flatten the negative electrode tab and place it on the placement table. According to the test requirements, take out the corresponding number and size of metal particles or non-metal particles and place them on the negative electrode plate; Lay the separator flat on the negative electrode plate, and then lay another layer of positive electrode plate flat; After the test materials are placed, cover the box cover, set the extrusion pressure, start the extrusion drive device, and set different gradient extrusion pressure values; when all gradient pressure tests are completed, the test ends; record the experimental results and analyze the influence of foreign object particles with different particle sizes on the battery electrode plates in different SOC states under different pressures.

[0013] The described test method for detecting the influence of foreign objects in the battery, preferably, the SOC states include: 0% SOC, 10% SOC, 30% SOC, 50% SOC, 70% SOC, and 100% SOC.

[0014] The described test method for detecting the influence of foreign objects in the battery, preferably, the metal foreign object particles are soaked in the electrolyte before the experiment for standby. The arrangement order of the test materials from bottom to top is a single-layer negative electrode plate, a separator, foreign object particles, and a positive electrode plate in sequence.

[0015] Due to the adoption of the above technical solutions, the present invention has the following advantages: 1. The test method of the present invention mainly uses a simple test device to place metal foreign objects between the positive and negative electrode plates in a fully charged or specific SOC state, and then simulates the pressure between the battery cells and the expansion force of the battery cells by applying pressure to make the positive and negative electrodes fit tightly, so as to judge the influence of the presence of metal foreign objects on the positive and negative electrode plates of the battery.

[0016] 2. The test method of the present invention is simple and highly operable; moreover, the test cost is very low, the test process is easy to control, and the observability is strong; it can test the influence of metal particles / non-metal particles with different particle sizes, different quantities, and different position distributions on the battery under different conditions such as pressure and temperature in a relatively short time. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is an axonometric view of a test device for judging the influence of the size of metal foreign object particles on the battery provided by an embodiment of the present invention; Figure 2 It is a front view of the test device for judging the influence of the size of metal foreign object particles on the battery provided by this embodiment of the present invention; Figure 3 It is a sectional view of the test device for judging the influence of the size of metal foreign object particles on the battery provided by this embodiment of the present invention; The reference numerals in the drawings are as follows: 1 - test operation box; 2 - placement table; 3 - extrusion plate; 4 - pressure sensor; 5 - foreign object storage box, 5 - 1 metal particle placement box, 5 - 2 non-metal particle placement box, 5 - 3 spare placement box; 6 - air extraction and ventilation device; 7 - box cover, 7 - 1 left box cover, 7 - 2 right box cover. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the present invention will be described clearly and completely below. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those of ordinary skill in the art to which the present invention pertains. The terms "first", "second", "third", "fourth" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. Terms such as "comprising" or "including" mean that the elements or items appearing before the term cover the elements or items listed after the term and their equivalents, without excluding other elements or items. Terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0020] For ease of description, spatial relative relationship terms may be used in the text to describe the relationship of one element or feature shown in the figure to another element or feature. These relative relationship terms such as "inner", "outer", "inner side", "outer side", "below", "above", etc. are intended to include different orientations of the device in use or operation other than the orientations depicted in the figure.

[0021] One of the prior arts discloses a safety test method and a test device for a battery. The safety test method is an evaluation method for evaluating the safety of a battery having an electrode group including a positive electrode plate, a negative electrode plate, and a separator inserted between the two, and includes the following steps: a step of charging the battery to a specified voltage; a step of mixing a conductive foreign object in the charged battery in a state of being in contact with the positive electrode plate and not in contact with the negative electrode plate; a step of immersing the battery mixed with the conductive foreign object in an electrolyte solution to dissolve and precipitate the conductive foreign object, thereby causing an internal short circuit in the battery; a step of evaluating the heat generation behavior of the battery in which the internal short circuit has occurred and outputting the evaluation result as a safety index. However, this prior art only evaluates the heat generation behavior of the battery in which the internal short circuit has occurred and does not involve the influence of the size of metal foreign object particles on the battery.

[0022] The second prior art discloses a foreign object detection device for a lithium battery pole piece laminator, including a laminator base. At the front part of the upper end of the laminator base, there is a pole piece picking and placing mechanism, which consists of two pole piece picking and placing stations distributed left and right. At the rear end of the pole piece picking and placing mechanism, there is a diaphragm unwinding mechanism. At the input end of the diaphragm unwinding mechanism, there is a diaphragm body. At the rear part of the upper end of the laminator base, there is a horizontal driving mechanism. At the upper end of the horizontal driving mechanism, there is a horizontal moving plate. At the left part of the upper end of the horizontal moving plate, there is a vertical driving mechanism. At the output end of the vertical driving mechanism, there is a lamination workbench. On the upper end of the lamination workbench, there is an electric core in the lamination process. At the rear part of the upper end of the horizontal moving plate, there is a pulse short-circuit tester. At the middle part of the upper end of the horizontal moving plate, there is a detection mechanism. At the rear part of the upper end of the laminator base, there is a gantry, and in the middle of the upper end of the horizontal part of the gantry, there is a set of convex teeth. This prior art can only detect foreign objects and cannot evaluate the impact of foreign objects on the battery.

[0023] The current mainstream test and verification method is to place metal foreign objects between the pole pieces inside the stacked core before assembling the test battery stack core, and then carry out subsequent process steps such as assembly and formation to finally complete the production of the test battery. However, this mainstream method has the following deficiencies: 1. The cycle for producing the test battery is very long and relatively dangerous; 2. If it is necessary to compare metal foreign objects with different particle sizes and different styles, the number of test batteries is large and the test cost is very high; 3. The test process is difficult to control and the test observability is not strong.

[0024] Based on the above technical problems, the present invention provides a device and method for detecting the impact of battery foreign objects. This device and test method can test the impact of metal particles / non-metal particles with different particle sizes, different quantities, and different position distributions on the battery under different conditions such as pressure and temperature in a relatively short time.

[0025] As Figure 1 、 3 shown, the device for detecting the impact of battery foreign objects involved in the present invention includes: a test operation box 1, and the test operation box 1 is a transparent box, and the tester can observe the situation inside the box at any time. The test operation box 1 includes a box body and a box cover 7 movably connected to the box body. On the inner bottom of the test operation box 1, there is a placement table 2 for carrying the electric core to be tested; a pressing plate 3 movably arranged on the inner wall of the box cover 7, and a pressure sensor 4 is arranged on the pressing plate 3; a pressing driving device, and the driving end of the pressing driving device penetrates the box cover 7 and is connected to the pressing plate 3 for driving the pressing plate 3 to press the electric core to be tested.

[0026] Furthermore, as Figure 1 shown, the test operation box 1 is also provided with an air extraction and ventilation device 6 arranged on the side wall of the test operation box 1.

[0027] Furthermore, as Figure 1 , 3 shown, a foreign object storage box 5 is further provided on the inner bottom of the test operation box 1. Preferably, the foreign object storage box 5 includes a metal particle placement box 5-1 and a non-metal particle placement box 5-2. More preferably, the foreign object storage box 5 further includes a spare placement box 5-3.

[0028] In some preferred examples of the present invention, as Figure 1 shown, the box cover 7 includes a left box cover 7-1 and a right box cover 7-2 which are separately arranged, and handles are provided on both the left box cover 7-1 and the right box cover 7-2.

[0029] The second aspect of the present invention also provides a test method for detecting the influence of battery foreign objects, and the specific operation method is as follows: Step 1: Place the test operation box 1 on the working platform of the cell disassembly test laboratory with controlled environmental temperature and humidity; Step 2: According to the requirements of different DOE tests, prepare metal foreign object particles with different particle sizes, and place the non-metal foreign object particles in the foreign object storage box 5 for standby; Step 3: Disassemble the batteries in different SOC states, and take out the positive and negative electrode plates for standby; Step 4: In the test session, lay the negative electrode tab flat on the marble plate in the test box. According to the test requirements, take out the corresponding number and size of metal particles or non-metal particles and place them on the negative electrode plate. The position and distribution on the electrode plate can be determined according to specific requirements; Step 5: After placing the metal particles or non-metal particles, place the corresponding separator flat on the negative electrode plate, and then lay a layer of positive electrode plate flat on it. The separator can be laid or not according to needs, but note that the aluminum foil should not accidentally contact the underlying negative electrode plate during the placement of the positive electrode plate. To prevent this from happening, the positive and negative electrode tabs can be wrapped with insulating tape before the experiment to play an insulating role; Step 6: After placing all the above test materials, cover the box cover, set the extrusion pressure, start the extrusion drive device. The pressure value of the extrusion can be set to different gradients according to needs, and each gradient stays for a period of time to observe the test phenomenon; when all the gradient pressure tests are completed, the test ends; record the experimental results, and based on the test results, conduct analysis, summary and induction to judge the influence of the foreign object particle size on the battery.

[0030] In the above method, the SOC states include: 0% SOC, 10% SOC, 30% SOC, 50% SOC, 70% SOC, 100% SOC, etc. Of course, batteries with other SOC ratio states can also be selected. The metal foreign object particles are soaked in the electrolyte and reserved before the experiment. The arrangement order of the test materials from bottom to top is a single-layer negative electrode sheet, a separator, the foreign object particles, and a positive electrode sheet.

[0031] The test method of the present invention mainly uses a simple test device to place the metal foreign object between the positive and negative electrode sheets in a fully charged or specific SOC state, and then simulates the pressure between the battery cells and the battery cell expansion force by pressurizing, so that the positive electrode and the negative electrode are closely attached to each other, thereby judging the influence of the presence of the metal foreign object on the positive and negative electrode sheets of the battery. This method is simple and highly operable; moreover, the test cost is very low, the test process is easy to control, and the observability is strong; it can test the influence of metal particles / non-metal particles with different particle sizes, different quantities, and different position distributions on the battery under different pressures, temperatures, etc. within a short time.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for detecting the influence of foreign objects on a battery, characterized in that, Comprising: A test operation box (1), the test operation box (1) includes a box body and a box cover (7) movably connected to the box body. A placement table (2) is provided on the inner bottom of the test operation box (1), and the placement table (2) is used to carry the battery cells to be tested; An extrusion plate (3) is movably arranged on the inner wall of the box cover (7), and a pressure sensor (4) is arranged on the extrusion plate (3); An extrusion driving device, the driving end of the extrusion driving device penetrates through the box cover (7) and is connected to the extrusion plate (3) for driving the extrusion plate (3) to extrude the battery cells to be tested.

2. The device for detecting the influence of foreign objects on the battery according to claim 1, wherein It further includes an air extraction and ventilation device (6) arranged on the side wall of the test operation box (1).

3. The device for detecting the influence of foreign objects on a battery according to claim 2, characterized in that, A foreign object storage box (5) is further provided on the inner bottom of the test operation box (1).

4. The device for detecting the influence of foreign objects on a battery according to claim 3, characterized in that, The foreign object storage box (5) includes a metal particle placement box (5-1) and a non-metal particle placement box (5-2).

5. The device for detecting the influence of foreign objects on a battery according to claim 4, characterized in that, The foreign object storage box (5) further includes a spare placement box (5-3).

6. The device for detecting the influence of foreign objects on a battery according to claim 1, wherein, The box cover (7) includes a left box cover (7-1) and a right box cover (7-2) which are separately arranged.

7. The device for detecting the influence of foreign objects on a battery according to claim 1, characterized in that, Both the left box cover (7-1) and the right box cover (7-2) are provided with handles.

8. A test method for detecting the influence of foreign objects on a battery, characterized in that, Including the following steps: Place the test operation box (1) on the working platform of the battery cell disassembly laboratory; According to the requirements of different DOE tests, prepare metal foreign object particles with different particle sizes, and place the non-metal foreign object particles in the foreign object storage box (5) for standby; Disassemble the batteries in different SOC states, and take out some positive and negative electrode plates therefrom for standby; In the test session, lay the negative electrode tab flat on the placement table (2), and according to the test requirements, take out the corresponding number and size of metal particles or non-metal particles and place them on the negative electrode plate; Lay the separator flat on the negative electrode plate, and then lay another layer of positive electrode plate; After the test materials are placed, cover the box cover (7), set the extrusion pressure, start the extrusion driving device, and set different gradient extrusion pressure values; when all the gradient pressure tests are completed, the test ends; record the experimental results and analyze the influence of foreign object particles with different particle sizes on the electrode plates of batteries in different SOC states under different pressures.

9. The test method for detecting the influence of foreign objects in a battery according to claim 8, wherein, The SOC states include: 0% SOC, 10% SOC, 30% SOC, 50% SOC, 70% SOC and 100% SOC.

10. The test method for detecting the influence of foreign objects on a battery according to claim 8, wherein The metal foreign object particles are soaked in the electrolyte for standby before the experiment, and the placement order of the test materials from bottom to top is a single layer of negative electrode plate, separator, foreign object particles and positive electrode plate.

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