Flat battery detection device and flat battery defect detection method

Abstract

The present invention discloses a flat-plate battery detection device and a flat-plate battery defect detection method, which belong to the field of battery detection technology. The flat-plate battery detection device includes an upper baffle and a lower baffle arranged in parallel, a narrow magnetic conductor, a narrow coil wound on the narrow magnetic conductor, a wide magnetic conductor, a wide coil wound on the wide magnetic conductor, the narrow magnetic conductor is vertically fixed to the upper baffle, and the wide magnetic conductor is vertically fixed to the lower baffle; the upper baffle and the lower baffle are both magnetic shielding materials, and the narrow magnetic conductor and the wide magnetic conductor are both magnetic conductive materials. A direct current is passed through the narrow coil and the wide coil respectively, forming a closed magnetic field between the narrow magnetic conductor and the wide magnetic conductor, and the charged flat-plate battery is connected to a load to form a discharge circuit, so that the flat-plate battery passes through the magnetic field formed by the narrow magnetic conductor and the wide magnetic conductor, and the change in current in the battery circuit is recorded, and whether the battery has defects is determined based on the change in current. The present invention can detect whether a flat-plate battery has defects without destroying it.

Description

Technical Field

[0001] The present invention relates to a flat battery testing device, belonging to the technical field of battery testing, and also relates to a method for detecting defects in flat batteries using the above-mentioned testing device. Background Art

[0002] Lithium-ion batteries are increasingly being used in response to energy-saving technologies. However, defects in lithium-ion batteries caused by factors such as lithium dendrite growth, assembly and installation failures, diaphragm damage, and compression shock can lead to short circuits after long-term operation. During a short circuit, the two electrode materials electronically interconnect internally, resulting in locally high current densities. Prolonged internal short circuits can lead to self-discharge and localized temperature increases. The impact of these localized temperature increases is significant because, if the temperature exceeds a certain threshold, the electrolyte can begin to decompose through an exothermic reaction, causing thermal runaway and posing potential health and safety risks.

[0003] The present invention provides a single-chip flat-plate battery detection device and detection method, which can screen out problematic batteries without affecting the battery operation, thereby avoiding safety hazards. Summary of the Invention

[0004] In view of the above-mentioned defects in the prior art, the present invention provides a flat-plate battery detection device with a simple structure and capable of detecting whether a flat-plate battery has defects without destroying the flat-plate battery.

[0005] The present invention is achieved through the following technical solution: a flat battery detection device, characterized in that it includes an upper baffle, a narrow magnetic conductor, a narrow coil, a lower baffle, a wide magnetic conductor, and a wide coil, the upper baffle and the lower baffle are arranged in parallel up and down, the narrow magnetic conductor is vertically fixed to the upper baffle, the narrow coil is wound on the narrow magnetic conductor, the wide magnetic conductor is vertically fixed to the lower baffle, and the wide coil is wound on the wide magnetic conductor, the narrow magnetic conductor and the wide magnetic conductor correspond to each other up and down, and the length L of the narrow magnetic conductor is the same as the length of the wide magnetic conductor; the upper baffle and the lower baffle are both made of magnetic shielding material, and the narrow magnetic conductor and the wide magnetic conductor are both made of magnetic conductive material.

[0006] Furthermore, the narrow magnetic conductor and the wide magnetic conductor are made of electrical silicon steel sheets or soft ferrite; and the upper baffle and the lower baffle are made of iron.

[0007] Furthermore, the length L of the narrow magnetic conductor is greater than the length L' of the planar battery.

[0008] Furthermore, the lower end of the narrow magnetic conductor is embedded in the interior of the upper baffle; the upper end of the wide magnetic conductor is embedded in the interior of the lower baffle.

[0009] When testing a flat-plate battery using the aforementioned flat-plate battery testing device, a direct current is first passed through the narrow coil and the wide coil, respectively. The direction of the current is adjusted so that opposite magnetic poles are formed at the relative positions of the narrow and wide magnetic conductors, thereby forming a closed magnetic field. Next, the charged flat-plate battery is connected to a load to form a discharge circuit. The flat-plate battery passes through the magnetic field formed by the narrow and wide magnetic conductors, and the changes in the current in the battery circuit are recorded. Based on the changes in the current, it is determined whether the battery has defects.

[0010] The beneficial effects of the present invention are: the present invention has a simple structure, can detect whether a flat battery has defects without destroying the flat battery, has a simple detection method, and has reliable detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural schematic diagram of the present invention;

[0012] Figure 2 is a schematic top view of the present invention;

[0013] Figure 3 is a schematic cross-sectional view of a flat-plate battery;

[0014] Figure 4 is a top view schematic diagram of a flat battery;

[0015] Figure 5 It is a schematic diagram of the testing process of the present invention;

[0016] Figure 6 This is a schematic diagram of the movement of lithium ions inside the battery under different conditions;

[0017] Figure 7 It is a schematic diagram of the battery circuit current change;

[0018] Figure 8 This is a schematic diagram of the battery circuit current change when there is a defect;

[0019] In the figure, 1. upper baffle, 2. narrow magnetic conductor, 3. narrow coil, 4. lower baffle, 5. wide magnetic conductor, 6. wide coil, 7. positive current collector, 8. positive pole of power supply, 9. diaphragm, 10. negative pole of power supply, 11. negative current collector, 12. negative pole tab, 13. positive pole tab, 14. flat battery. DETAILED DESCRIPTION

[0020] The present invention will be further described below by way of non-limiting embodiments with reference to the accompanying drawings:

[0021] As shown in the accompanying drawings, a flat-plate battery testing device includes an upper baffle 1, a narrow magnetic conductor 2, a narrow coil 3, a lower baffle 4, a wide magnetic conductor 5, and a wide coil 6. The upper baffle 1 and the lower baffle 4 are both flat-plate structures and are arranged parallel to each other. The upper baffle 1 and the lower baffle 4 are both made of magnetic shielding materials, such as iron. The narrow magnetic conductor 2 and the wide magnetic conductor 5 are both made of magnetic conductive materials, such as electrical silicon steel sheets, soft magnetic ferrite, etc. The narrow magnetic conductor 2 is a cubic structure and is vertically fixed to the upper baffle 1. Preferably, the lower end of the narrow magnetic conductor 2 is embedded in the upper baffle 1. The length L of the narrow magnetic conductor 2 is preferably greater than the length L' of the flat-plate battery. The narrow coil 3 is wrapped around the outer periphery of the narrow magnetic conductor 2 to generate a magnetic field. The wide magnetic conductor 5 is a cubic structure and is vertically fixed to the upper and lower baffles 5. Preferably, the upper end of the wide magnetic conductor 5 is embedded in the lower baffle 5. The wide coil 6 is wound around the wide magnetic conductor 5 to generate a magnetic field. The narrow magnetic conductor 2 and the wide magnetic conductor 5 correspond to each other vertically, and the length L of the narrow magnetic conductor 2 is the same as the length of the wide magnetic conductor 5.

[0022] The method for testing a flat-plate battery using the above-mentioned flat-plate battery testing equipment is as follows: first, a direct current is passed through the narrow coil 3 and the wide coil 6, respectively, and the direction of the current is adjusted so that opposite magnetic poles are formed at the relative positions of the narrow magnetic conductor 2 and the wide magnetic conductor 5, thereby forming a closed magnetic field; then, the charged flat-plate battery is connected to a load to form a discharge circuit, so that the flat-plate battery passes through the magnetic field formed by the narrow magnetic conductor 2 and the wide magnetic conductor 5, and the changes in the current in the battery circuit are recorded. Based on the changes in the current, it is determined whether the battery has a defect.

[0023] The working principle and specific detection process of the present invention are as follows:

[0024] As attached Figure 6 As shown in Figure (a), during the normal discharge process of a flat-plate battery, lithium ions migrate from the negative electrode (bottom of the diagram) to the positive electrode (top of the diagram), passing through the positive electrode into the external circuit, generating a current. Ideally, the current density is uniform across the thickness of the battery, and the discharge current remains stable.

[0025] During the working process of the present invention, the upper baffle 1 and the lower baffle 4 are first fixed, and the distance between the two baffles is slightly larger than the thickness of the flat battery. Then, electricity is applied inside the narrow coil 3 and the wide coil 6 to form a gap between the two baffles. Figure 5 The magnetic field shown in the figure is used to connect the flat battery to an external load to discharge the battery and record the loop current. Before testing the battery, the magnetic field strength is adjusted first, the battery is moved into the magnetic field, and the current changes are recorded. The excitation current of the narrow coil 3 and the wide coil 6 is increased until the external loop current decreases after the battery enters the magnetic field. This shows that the magnetic field affects the movement of lithium ions. Figure 6As shown in (b), due to the confinement of the magnetic field, the path of lithium ions from the negative electrode to the positive electrode of the battery increases and the total current decreases.

[0026] The magnetic field remains fixed, the flat battery to be tested forms a discharge loop, and moves through the magnetic field area to test the current change characteristics. If the battery has no defects, its current change is as follows Figure 7 shown.

[0027] When there are defects inside the battery, such as Figure 6 As shown in (c), there is a gap in the battery diaphragm. When the defect position enters the magnetic field range, the current density at the magnetic field position is greater than the current density at the non-magnetic field position. The effect of the defect on the current will be more obvious. A large number of lithium ions will move directly to the negative electrode of the battery without the obstruction of the diaphragm, and the current density will increase slightly. Figure 8 shown.

[0028] When there are defects inside the battery, such as Figure 6 As shown in (d), when there is deformation inside the battery, the positive plate is concave inward. Since the current density at the magnetic field position is greater than the current density at the non-magnetic field position, the effect of the defect on the current will be more obvious, and the movement path of a large number of lithium ions will be shortened, and the current density will increase slightly. Figure 8 shown.

[0029] Therefore, defects in the battery's internal diaphragm or internal structure can be detected through changes in the discharge current.

[0030] The other parts of this embodiment are all existing technologies and will not be described in detail here.

[0031] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A flat battery testing device, characterized by: The invention comprises an upper baffle, a narrow magnetic conductor, a narrow coil, a lower baffle, a wide magnetic conductor, and a wide coil. The upper baffle and the lower baffle are arranged in parallel up and down. The narrow magnetic conductor is vertically fixed to the upper baffle. The narrow coil is wound on the narrow magnetic conductor. The wide magnetic conductor is vertically fixed to the lower baffle. The wide coil is wound on the wide magnetic conductor. The narrow magnetic conductor and the wide magnetic conductor correspond to each other up and down. The length L of the orthographic projection of the narrow magnetic conductor on the upper baffle is the same as the length of the orthographic projection of the wide magnetic conductor on the lower baffle. The upper baffle and the lower baffle are both made of magnetic shielding materials. The narrow magnetic conductor and the wide magnetic conductor are both made of magnetic conductive materials. During testing, the upper and lower baffles are fixed, and the distance between the two baffles is slightly larger than the thickness of the flat battery; DC current is respectively passed through the narrow coil and the wide coil, and the direction of the current is adjusted so that opposite magnetic poles are formed at the relative positions of the narrow magnetic conductor and the wide magnetic conductor, thereby forming a closed magnetic field.

2. The flat battery testing device according to claim 1, wherein: The narrow magnetic conductor and the wide magnetic conductor are both electrical silicon steel sheets or soft ferrites; the upper baffle and the lower baffle are made of iron.

3. The flat battery testing device according to claim 1 or 2, characterized in that: The lower end of the narrow magnetic conductor is embedded in the interior of the upper baffle; the upper end of the wide magnetic conductor is embedded in the interior of the lower baffle.

4. A flat battery defect detection method, characterized by: A flat-plate battery testing device according to any one of claims 1 to 3 is used to test a flat-plate battery; first, a direct current is passed through the narrow coil and the wide coil, respectively, and the direction of the current is adjusted so that opposite magnetic poles are formed at the relative positions of the narrow magnetic conductor and the wide magnetic conductor, thereby forming a closed magnetic field; Then, the charged flat-plate battery is connected to a load to form a discharge circuit, so that the flat-plate battery passes through the magnetic field formed by the narrow magnetic conductor and the wide magnetic conductor, and the changes in the current in the battery circuit are recorded. Based on the changes in the current, it is determined whether the battery has defects.

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