Battery pack for simply testing pressure between battery cells

Abstract

The utility model discloses a battery pack for simply testing the pressure between battery cells, which comprises a battery shell and the battery cells, the battery cells are assembled in the battery shell, a pressure testing assembly is further arranged in the battery shell, and the pressure testing assembly comprises first white paper, carbon paper and second white paper which are sequentially stacked together. The utility model aims to solve the technical problems in the prior art, provides the battery pack for simply testing the pressure between the battery cells, can be used for testing the full size of the battery cells, cannot cause larger errors due to point taking problems, and is simple in structure, convenient to test and low in cost.

Description

Technical Field

[0001] The utility model relates to the technical field of battery packs, and in particular to a battery pack for simply testing the pressure between battery cells. Background Art

[0002] Pressure parameters have a profound impact on the electrical performance, cycle performance and safety performance of lithium-ion battery products throughout the life cycle. Smaller pressure may cause the interface between cells to be loose. If slight gas production occurs, it will greatly increase the internal resistance of the cell and accelerate product failure. Larger pressure may cause excessive stress during charging, making lithium insertion difficult, and increase the risk of lithium dendrites forming at the negative electrode interface, thereby affecting the cycle performance and safety performance of the cell. Therefore, the study of the stress state of the cell in the initial or working state in the battery pack is of great significance for the feedback of product design and the deepening of the understanding of product performance.

[0003] At present, the method of detecting the pressure between cells in a battery pack is generally to use a thin film sensor. However, high-precision thin film sensors are expensive, and their sensor sensing area is limited, making it difficult to characterize the pressure parameters of different areas on the entire surface of the cell. Therefore, a simple, convenient, low-cost method and device that can simultaneously detect the force conditions of various locations on the large surface of the cell is urgently needed to be developed. Utility Model Content

[0004] 1. Technical problems to be solved by the utility model

[0005] The utility model aims to solve the technical problems existing in the prior art and provide a battery pack for simply testing the pressure between battery cells. The utility model can test the full size of the battery cells without causing large errors due to point selection problems, and has a simple structure, convenient testing and low price.

[0006] 2. Technical solution

[0007] In order to solve the above problems, the technical solution provided by the utility model is:

[0008] A battery pack for simply testing the pressure between battery cells comprises a battery shell and a battery cell. The battery cell is assembled in the battery shell. A pressure test assembly is also arranged in the battery shell. The pressure test assembly comprises a first white paper, a carbon paper and a second white paper stacked together in sequence.

[0009] Optionally, the side wall of the battery shell in contact with the pressure testing assembly is a detachable structure.

[0010] Optionally, the battery shell includes a fixed shell and a disassembly shell, the fixed shell is provided with an inlet and outlet of a pressure test assembly, and the disassembly shell is detachably connected to the fixed shell for sealing the inlet and outlet of the pressure test assembly.

[0011] Optionally, the disassembly shell is detachably connected to the fixed shell via a locking structure.

[0012] Optionally, the disassembly shell includes an external connection shell and an internal pressure block, the external connection shell abuts against an outer side wall of the fixed shell, and the internal pressure block extends into the fixed shell through the inlet and outlet of the pressure test assembly.

[0013] Optionally, the outer diameter of the internal pressure block is adapted to the inner diameter of the inlet and outlet of the pressure testing assembly.

[0014] 3. Beneficial effects

[0015] Compared with the prior art, the technical solution provided by the utility model has the following beneficial effects:

[0016] 1. The full size of the battery cell can be tested without large errors caused by point selection issues.

[0017] 2. The battery shell has a detachable side, which avoids the need to remove the entire battery when comparing the marks after each test. It is simple and convenient

[0018] 3. The depth and position between the removable side and the battery fixed shell are positioned by the slot step limiter. The depth limiter prevents the change of the reserved size of the shell to the module during disassembly and assembly, which affects the pressure test value. The position limiter prevents the displacement of the imprint from changing, which increases the difficulty of comparison. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the structure of a battery pack for simply testing the pressure between cells proposed in an embodiment of the utility model;

[0020] Figure 2 A cross-sectional schematic diagram of a battery pack for simply testing the pressure between battery cells proposed in an embodiment of the utility model;

[0021] Figure 3 A test flow chart of a battery pack for simply testing the pressure between cells proposed in an embodiment of the utility model;

[0022] Figure 4 A carbon paper pressure-imprint image MAP model of a battery pack for simply testing the pressure between cells proposed in an embodiment of the utility model;

[0023] 1. Battery shell; 11. Fixed outer shell; 12. Disassembly shell; 121. External connection shell; 122. Internal pressure block; 2. Battery cell module; 3. Pressure test assembly; 4. Locking structure. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be understood that the specific implementation methods described here are only used to explain the utility model and do not limit the protection scope of the utility model.

[0025] It should be noted that when an element is referred to as being "fixed to", "disposed on", "fixed on" or "installed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. Further, when an element is considered to be "fixedly connected to" another element, the two may be fixed in a detachable connection manner or in a non-detachable connection manner, such as socketing, snap-on, one-piece fixation, welding, etc., which can be achieved in the prior art and will not be repeated here. When an element is perpendicular or approximately perpendicular to another element, it means that the ideal state of the two is vertical, but due to the influence of manufacturing and assembly, there may be a certain vertical error. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0027] The “first” and “second” involved in the present invention do not represent specific quantities and orders, but are merely used to distinguish names.

[0028] Combined with Figure 1-4 A battery pack for simply testing the pressure between battery cells in this embodiment includes a battery shell 1 and a battery cell module 2, wherein the battery cell module 2 is assembled in the battery shell 1, and a pressure test component 3 is also provided in the battery shell 1, wherein the pressure test component 3 is clamped between the side wall of the battery shell 1 and the battery cell module 2, and the pressure test component 3 is provided at one end of the battery cell module 2 along the battery cell stacking direction, and the pressure test component 3 includes a first white paper, a carbon paper, and a second white paper stacked together in sequence, and the pressure test component 3 is a sandwich structure. After the required test, the pressure test component 3 is taken out, and the marks on the first white paper and the second white paper are compared with the carbon paper pressure-image MAP model to obtain the force magnitude.

[0029] The construction method of the carbon paper pressure-imprint image MAP model is to stack white paper and carbon paper between the pressurizing devices, pressurize the white paper and the carbon paper to different degrees, and retain the imprint depth of the carbon paper on the white paper under different pressures. The carbon paper pressure-imprint image MAP model is as follows: Figure 4 shown.

[0030] As an optional solution of the present invention, the side wall of the battery shell 1 in contact with the pressure test assembly 3 is a detachable structure to facilitate the rapid removal of the pressure test assembly 3 and avoid compression of the pressure test assembly 3 during the removal process that affects the test results.

[0031] As an optional solution of the present invention, the battery shell 1 includes a fixed shell 11 and a disassembly shell 12, the battery cell module 2 is installed in the fixed shell 11, and the fixed shell 11 is provided with an inlet and outlet of a pressure test assembly. The size of the inlet and outlet of the pressure test assembly is at least sufficient to ensure that the pressure test assembly 3 will not be squeezed and deformed when entering and exiting. The disassembly shell 12 can be detachably connected to the fixed shell 11 to seal the inlet and outlet of the pressure test assembly.

[0032] As an optional solution of the present invention, the disassembly shell 12 is detachably connected to the fixed shell 11 through a locking structure 4. The locking structure 4 can use an existing locking connection structure on the market, or can be connected by a snap-on method.

[0033] As an optional solution of the present invention, the disassembly shell 12 includes an external connection shell 121 and an internal pressure block 122, the external connection shell 121 abuts against the outer wall of the fixed shell 11, and the internal pressure block 122 extends into the fixed shell 11 through the inlet and outlet of the pressure testing assembly, and the external connection shell 121 abuts against the outer wall of the fixed shell 11 to limit the depth of the internal pressure block 122, so as to avoid the change of the reserved size of the shell for the module during disassembly and assembly, which affects the pressure test value.

[0034] As an optional solution of the present invention, the outer diameter of the internal pressure block 122 is adapted to the inner diameter of the inlet and outlet of the pressure testing assembly, thereby ensuring that the position of the internal pressure block 122 extending into the fixed outer shell 11 always remains consistent, avoiding changes in the imprint displacement that increase the difficulty of comparison.

[0035] The specific steps of this simple test of the pressure between cells of the battery pack are as follows:

[0036] 1. Add white paper and carbon paper to the pressurizing equipment room, pressurize the white paper and carbon paper to different degrees, retain the imprint depth of the carbon paper on the white paper under different pressures, and build a carbon paper pressure-imprint image MAP model;

[0037] 2. Cut the white paper and carbon paper into the same size or slightly larger than the large surface of the battery cell;

[0038] 3. Stack the cut white paper and carbon paper between the module and the specially designed detachable side wall of the battery shell to form a sandwich structure of battery cell-white paper-carbon paper-white paper-battery shell;

[0039] 4. Assemble the battery pack normally, perform the required tests, disassemble the battery pack, remove the shell, take out the white paper and carbon paper, and compare the imprint on the white paper with the carbon paper pressure-image MAP model to obtain the force magnitude;

[0040] 5. If you need to monitor the pressure of the test step under another design condition again, just fill the module with carbon paper and white paper again, close the disassembly shell, and test again. The battery pack disassembly shell is connected to the battery pack fixed shell by a lock; the disassembly shell and the fixed shell are fixed by a slot step limiter to fix the disassembly depth and disassembly position, ensuring the consistency of the internal dimensions and force position of the battery shell.

[0041] Embodiment 1

[0042] 1. Take two 25Ah soft-pack batteries with a size of 7.5*138*210mm, two pieces of white paper and a piece of carbon paper with the same size of 138*210mm, stack the above items in the order of battery cell-white paper-carbon paper-white paper-battery cell, place them on the pressure thickness measuring equipment, and perform repeated pressure tests on the above stacked samples. After each pressure test, replace the white paper and carbon paper. The pressure starts from 100N and increases to 2400N. Test 13 times in total until the pressure increases to 2400N, and obtain the carbon paper pressure-imprint image MAP model;

[0043] 2. Use 15 pcs of the above 25Ah cells to assemble into a 48V25Ah two-wheeled vehicle battery pack in series, and place white paper-carbon paper-white paper between the stacked series cells and the large surface of the removable battery shell to assemble into a complete battery pack;

[0044] 3. Charge the battery pack at 1C until it reaches 54.75V or the single cell reaches 3.65V, let it stand for 30 minutes, and then discharge it at 1C until it reaches 37.5V or the single cell reaches 2.5V;

[0045] 4. Remove the removable outer shell of the battery pack and take out the white paper and carbon paper;

[0046] 5. Compare the mark on the white paper at this time with the image MAP obtained in 1 to obtain the pressure value.

[0047] The above schematically describes the present invention and its implementation methods, which are not restrictive. The drawings show only one implementation method of the present invention, and the actual structure is not limited thereto. Therefore, if ordinary technicians in this field are inspired by it and design structural methods and embodiments similar to the technical solution without creativity without departing from the purpose of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A battery pack for simply testing the pressure between cells, characterized in that: It includes a battery shell and a battery cell module, wherein the battery cell module is assembled in the battery shell. A pressure test assembly is also arranged in the battery shell, and the pressure test assembly includes a first white paper, a carbon paper and a second white paper stacked together in sequence.

2. A battery pack for simply testing the pressure between cells according to claim 1, characterized in that: The side wall of the battery shell in contact with the pressure testing assembly is a detachable structure.

3. A battery pack for simply testing the pressure between cells according to claim 2, characterized in that: The battery shell includes a fixed shell and a disassembly shell. The fixed shell is provided with an inlet and outlet of a pressure test assembly. The disassembly shell is detachably connected to the fixed shell for sealing the inlet and outlet of the pressure test assembly.

4. A battery pack for simply testing the pressure between cells according to claim 3, characterized in that: The disassembly shell is detachably connected to the fixed shell through a locking structure.

5. A battery pack for simply testing the pressure between cells according to claim 3, characterized in that: The disassembly shell includes an external connection shell and an internal pressure block. The external connection shell abuts against the outer side wall of the fixed shell, and the internal pressure block extends into the fixed shell through the inlet and outlet of the pressure test assembly.

6. A battery pack for simply testing the pressure between cells according to claim 5, characterized in that: The outer diameter of the inner pressure block is adapted to the inner diameter of the inlet and outlet of the pressure testing assembly.

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