Tripolar column type square shell battery

Abstract

The utility model provides a three-pole type square-shell battery, which relates to the technical field of lithium batteries, and comprises a shell, a naked battery cell is mounted at the top of the shell, and the naked battery cell is formed by winding or folding a cathode plate, an anode plate and a diaphragm; the lithium sheet is arranged in the naked battery cell, a copper strip is arranged on the outer wall of the lithium sheet, and the outer surfaces of the two sides of the lithium sheet are covered with covering films; a top cover is mounted at the top of the shell, two pole columns and a reference electrode are arranged in the top cover, the copper strip is connected with the reference electrode, the diaphragm is arranged between the cathode plate and the anode plate, tabs are cut at the tops of the cathode plate and the anode plate, the positive tab is electrically connected with the positive pole column, the negative tab is electrically connected with the negative pole column, and the copper strip is connected with the diaphragm. The copper strip is formed by folding a copper foil material in a Z shape, the number of folded layers is not less than two, the width of the copper strip is 0.5 cm-2 cm, compared with a traditional copper wire, the copper strip is not prone to breakage, and current transmission is smoother.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery technology, and more specifically, to a triode-type prismatic battery. Background Technology

[0002] In the context of the energy crisis and the new situation of green environmental protection, lithium-ion batteries are increasingly being used in new energy or hybrid rail transit equipment due to their superior characteristics. Because the failure problem of lithium-ion batteries is relatively complex, the three-electrode system, used to monitor potential changes during overcharging, has become an important tool for analyzing lithium-ion battery failures.

[0003] Existing technologies primarily employ the copper wire lithium plating method, which uses copper wire as a reference electrode. First, the copper wire is immersed in sulfuric acid to remove the surface paint layer. Then, it needs to be lithium plated, i.e., a small current is used to charge the reference electrode from the positive electrode, depositing lithium ions onto the surface of the copper wire. This technology has several problems: 1. The amount of lithium plating on the copper wire is small and consumed quickly during testing, leading to inaccurate potential monitoring; 2. Copper wire is difficult to process, hard to connect, and prone to breakage, resulting in a low success rate in preparing three-electrode batteries.

[0004] Therefore, it is particularly important to develop a stable and reliable triode-type prismatic battery structure. Utility Model Content

[0005] The technical problem to be solved by this utility model is that the three electrodes used to monitor the potential change of lithium-ion batteries during overcharging have low lithium plating on the copper wire, are difficult to process, difficult to connect, and are easy to break. In view of the problems existing in the prior art, a three-electrode cylindrical square-shell battery is provided.

[0006] The purpose and effects of this utility model are achieved by the following specific technical means:

[0007] A triode cylindrical prismatic battery, comprising:

[0008] The housing has a bare battery cell mounted on top. The bare battery cell is made by winding or folding a cathode plate, an anode plate, and a diaphragm.

[0009] A lithium sheet is disposed inside a bare battery cell. The outer wall of the lithium sheet is provided with a copper strip, and both outer surfaces of the lithium sheet are covered with a film.

[0010] The top of the housing is fitted with a top cover, and the top cover contains two pole posts and a reference electrode. The copper strip is connected to the reference electrode.

[0011] A further preferred embodiment: the diaphragm is disposed between the cathode plate and the anode plate, and the top of the cathode plate and the anode plate are cut with tabs, which are positive tabs and negative tabs, respectively;

[0012] The two terminals on the top cover are a positive terminal and a negative terminal, respectively. The positive terminal tab is electrically connected to the positive terminal, and the negative terminal tab is electrically connected to the negative terminal.

[0013] A further preferred embodiment: the lithium sheet is located between a cathode sheet and an anode sheet, and the coating completely covers the lithium sheet and the connection between the copper strip and the lithium sheet, and the lithium sheet does not contact the cathode sheet or the anode sheet.

[0014] A further preferred embodiment: the copper strip is made of copper foil folded in a Z-shape, with no less than 2 folds, and the width of the copper strip is 0.5cm-2cm.

[0015] A further preferred embodiment: the width of the lithium sheet is greater than or equal to the width of the copper strip, and the widest part of the lithium sheet does not exceed twice the width of the copper strip.

[0016] A further preferred embodiment: the copper strip is made of copper foil substrate with a thickness of 1μm-5μm, and the total thickness after folding is 5μm-8μm.

[0017] The beneficial effects of this utility model are:

[0018] The copper strip is made of copper foil folded in a Z-shape with no less than two folds. The width of the copper strip is 0.5cm-2cm. Compared with traditional copper wire, it is less prone to breakage, and the current transmission is smoother, which can better measure the potential and current of electrochemical reactions.

[0019] The copper strip uses copper foil substrate with a thickness of 1μm-5μm, and the total thickness after folding is 5μm-8μm. The copper strip becomes thicker after being folded in a Z-shape, making it less prone to breakage and extending its service life.

[0020] The reference electrode monitors the positive and negative electrode potentials during destructive safety tests such as overcharging. The built-in lithium sheet ensures sufficient lithium content and stability on the reference electrode, while simplifying the preparation process of copper wire processing. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings.

[0022] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0023] Figure 2 This is a schematic diagram showing the bare cell structure and lithium sheet of this utility model.

[0024] Figure 3 This is a schematic diagram of the folding of the copper strip structure of this utility model.

[0025] Figures 1-3In the middle: shell (1), cathode plate (2), anode plate (3), lithium plate (4), copper strip (5), reference electrode (6), coating (7), electrode post (8). Detailed Implementation

[0026] To better understand the above-mentioned objectives, features, and advantages of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are merely examples for implementing this utility model. It must be pointed out that the disclosed embodiments do not limit the scope of this utility model. On the contrary, any modifications and refinements made without departing from the scope of this utility model are within the patent protection scope of this utility model.

[0027] Please see Figures 1-3 A three-electrode prismatic battery, comprising:

[0028] Housing 1, with a bare battery cell mounted on its top. The bare battery cell is made by winding or folding a cathode plate 2, an anode plate 3, and a diaphragm. The diaphragm is positioned between the cathode plate 2 and the anode plate 3. Figure 2 (As shown) In this embodiment, it is preferably folded. The top of the cathode plate 2 and the anode plate 3 are cut with tabs. The tabs are protruding and are the positive tab and the negative tab, respectively.

[0029] The top of the casing 1 is equipped with a top cover, and the top cover is provided with two terminals 8 and a reference electrode 6. The two terminals 8 on the top cover are the positive terminal 8 and the negative terminal 8, respectively. In the bare cell, the positive electrode tab is electrically connected to the positive terminal 8, and the negative electrode tab is electrically connected to the negative terminal 8. The positive terminal 8 is made of aluminum, and the negative terminal 8 is a copper-aluminum composite terminal 8. The top cover is welded to the casing 1 to form a square battery, and electrolyte is injected to activate the lithium battery.

[0030] Lithium foil 4 is disposed inside the bare cell. A copper strip 5 is disposed on the outer wall of lithium foil 4. The copper strip 5 is made of copper foil folded in a Z-shape, with at least two folds. The width of the copper strip 5 is 0.5cm-2cm. Compared with traditional copper wire, it is less prone to breakage, facilitates smoother current transmission, and allows for better measurement of the potential and current of electrochemical reactions. Lithium foil 4 is placed inside the bare cell during the folding process of cathode plate 2, anode plate 3, and separator. It can be placed in any layer of separator between cathode plate 2 and anode plate 3 for better monitoring of positive and negative electrode potentials. The copper strip 5 is preferably placed in the center layer of the bare cell, and then the copper strip 5 is placed in the lithium sheet 4, with one end of the copper strip 5 adjacent to the center of the lithium sheet 4. The copper strip 5 and the lithium sheet 4 can be fixed by welding head pressing. Then the coating 7 is covered on both sides of the lithium sheet 4. In order to maintain the consistency of the cell, the coating 7 is made of the same material as the separator used in the bare cell, preferably polytetrafluoroethylene. The coating 7 completely covers the lithium sheet 4 and covers the connection between the copper strip 5 and the lithium sheet 4, so that the lithium sheet 4 does not contact the cathode plate 2 and the anode plate 3, thus avoiding short circuit of the cell.

[0031] The copper strip 5 uses copper foil as its base material with a thickness of 1μm-5μm, and the total thickness after folding is 5μm-8μm. The copper strip 5 becomes thicker after being folded in a Z-shape, making it less prone to breakage and extending its service life.

[0032] like Figure 1 As shown, the lithium sheet 4 is connected to the copper strip 5. The copper strip 5 extends out of the cell and acts as the third electrode tab. The copper strip 5 is laser-welded to the reference electrode 6. The reference electrode 6 is a copper-aluminum composite electrode post 8. It is a three-electrode battery that can monitor the positive and negative electrode potentials during destructive safety tests such as overcharging. It ensures sufficient lithium content and stability on the reference electrode 6, while simplifying the preparation process of copper wire processing.

[0033] Preferably, the width of the lithium sheet 4 is greater than or equal to the width of the copper strip 5, and the maximum width of the lithium sheet 4 is no more than twice the width of the copper strip 5, so as to ensure the structural ratio between the copper strip 5 and the lithium sheet 4 and avoid affecting the test results due to size mismatch.

Claims

1. A three-electrode cylindrical prismatic battery, characterized in that, include: The housing has a bare battery cell mounted on top. The bare battery cell is made by winding or folding a cathode plate, an anode plate, and a diaphragm. A lithium sheet is disposed inside a bare battery cell. The outer wall of the lithium sheet is provided with a copper strip, and both outer surfaces of the lithium sheet are covered with a film. The top of the housing is fitted with a top cover, and the top cover contains two pole posts and a reference electrode. The copper strip is connected to the reference electrode.

2. A triode cylindrical prismatic battery according to claim 1, characterized in that: The diaphragm is disposed between the cathode plate and the anode plate, and the top of the cathode plate and the anode plate are cut with tabs, which are positive tabs and negative tabs, respectively; The two terminals on the top cover are a positive terminal and a negative terminal, respectively. The positive terminal tab is electrically connected to the positive terminal, and the negative terminal tab is electrically connected to the negative terminal.

3. A triode cylindrical prismatic battery according to claim 1, characterized in that: The lithium sheet is located between a cathode sheet and an anode sheet, and the coating completely covers the lithium sheet and the connection between the copper strip and the lithium sheet. The lithium sheet does not contact the cathode sheet or the anode sheet.

4. A triode cylindrical prismatic battery according to claim 1, characterized in that: The copper strip is made of copper foil folded in a Z-shape, with no less than 2 folds, and the width of the copper strip is 0.5cm-2cm.

5. A triode cylindrical prismatic battery according to claim 4, characterized in that: The width of the lithium sheet is greater than or equal to the width of the copper strip, and the widest part of the lithium sheet does not exceed twice the width of the copper strip.

6. A triode cylindrical prismatic battery according to claim 4, characterized in that: The copper strip is made of copper foil substrate with a thickness of 1μm-5μm, and the total thickness after folding is 5μm-8μm.

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