Cylindrical battery with in-situ reference electrode

Abstract

The utility model provides a cylindrical battery with in-situ reference electrodes, which belongs to the field of cylindrical batteries and comprises a shell, a top cover, a roll core and a rubber stick, one end of a first reference electrode is inserted into a through hole and clamped between the outer wall of the rubber stick and the inner wall of the through hole, and the other end of the first reference electrode extends towards the top cover; one end of the second reference electrode clings to the peripheral surface of the roll core, and the other end extends towards the top cover; two perforation parts are arranged on the top cover at intervals; and the first reference electrode and the second reference electrode respectively penetrate through the two perforation parts, extend outwards and are led out of the shell. According to the utility model, the two reference electrodes are respectively inserted into the through hole of the roll core and the periphery of the roll core and are led out of the shell through the perforation part, so that the problem that the cylindrical roll core needs to be opened when the reference electrodes are mounted to cause damage to a pole piece is avoided, the mounting method of the cylindrical reference electrodes is simplified, and the inner and outer reference electrodes can cooperate with reference data; accurate and effective electrode potential data of the positive and negative electrodes of the battery are ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of cylindrical batteries, in particular to a cylindrical battery with an in-situ reference electrode. Background Art

[0002] Three-electrode batteries are commonly used to monitor the positive and negative electrode potentials during battery charging and discharging, determine fast-charging boundaries, optimize charging strategies, and study battery failure mechanisms. Currently, most cylindrical three-electrode batteries are constructed by disassembling the tail of the winding core before inserting it into the shell. Treated copper wire is then embedded in the core, and two layers of separators are added between the positive and negative electrodes. The treated copper wire is then inserted between the separators and then drawn out through the injection hole. It is then injected with liquid and divided into different capacities along with the normally circulating battery cells. The difference is that the copper wire must be protected. After the division is completed, charging and lithium plating are performed to form a reference electrode.

[0003] Chinese patent CN107607873A discloses an in-situ three-electrode cylindrical battery and its preparation method. However, the reference electrode in the above three-electrode battery is affected by the preparation process, geometric dimensions and setting position, and has disadvantages such as poor stability, short life and complex processing, and is only suitable for short-term testing. During the long-term and multiple charge and discharge processes of the battery, the lithium metal deposited on the reference electrode is easy to fall off or react with the electrolyte, and there is a situation where the electrode itself fails or an overpotential is formed, resulting in data distortion. In addition, most cylindrical batteries currently use multi-tab or full-tab processes, especially full-tab cylinders need to be flattened, and the process of opening the core and inserting the reference electrode can easily damage the pole piece or tab. Utility Model Content

[0004] In view of this, the present invention proposes a cylindrical battery with an in-situ reference electrode, which avoids the problem of easily damaging the electrode sheet or the tab during the process of opening the winding core and inserting the reference electrode when installing the reference electrode.

[0005] The technical solution of the present invention is implemented as follows: the present invention provides a cylindrical battery with an in-situ reference electrode, comprising a shell with an opening on the top; a top cover arranged on the top of the shell; a winding core arranged in the shell and having a through hole in the center; a glue stick inserted in the through hole; a first reference electrode, one end of which is inserted in the through hole and clamped between the outer wall of the glue stick and the inner wall of the through hole, and the other end extends toward the top cover; a second reference electrode, one end of which is tightly attached to the outer circumference of the winding core, and the other end of which extends toward the top cover; wherein, two perforated portions are arranged at intervals on the top cover, and the first reference electrode and the second reference electrode respectively extend outward through the two perforated portions and are led out of the shell.

[0006] On the basis of the above technical solution, preferably, the first reference electrode and the second reference electrode both include a negative electrode sheet, a positive electrode sheet and a diaphragm; the negative electrode sheet is tightly attached to the outer circumference of the rubber stick or the winding core, and the negative electrode sheet, the diaphragm, the positive electrode sheet and the other diaphragm are arranged from the inside to the outside and fit together to form the first reference electrode or the second reference electrode; each perforated portion is provided with two through holes, and the free ends of the negative electrode sheet and the positive electrode sheet respectively extend outward through the two through holes and are led out of the shell.

[0007] More preferably, the negative electrode sheet is made of copper foil, and the positive electrode sheet is made of aluminum foil.

[0008] More preferably, portions of the negative electrode sheet and the positive electrode sheet extending outward from the winding core are both wrapped with tape.

[0009] More preferably, the length of the portion of the negative electrode sheet wrapped with the tape along its extending direction is greater than the length of the portion of the positive electrode sheet wrapped with the tape along its extending direction.

[0010] More preferably, the separator covers the portion of the negative electrode sheet and the positive electrode sheet that is not wrapped with the tape.

[0011] More preferably, the area of ​​the negative electrode sheet covered by the diaphragm is larger than the area of ​​the portion of the negative electrode sheet not wrapped with the tape, and the area of ​​the positive electrode sheet covered by the diaphragm is larger than the area of ​​the portion of the positive electrode sheet not wrapped with the tape.

[0012] More preferably, the surface of the positive electrode sheet facing the negative electrode sheet is coated with a positive electrode material.

[0013] More preferably, the positive electrode material is lithium iron phosphate slurry.

[0014] More preferably, after the first reference electrode and the second reference electrode pass through the perforated portion and are led out of the housing, a structural adhesive is applied to the outer surface of the perforated portion to seal the through-holes.

[0015] Compared with the prior art, the cylindrical battery with an in-situ reference electrode of the present invention has the following advantages:

[0016] Beneficial effects:

[0017] (1) The utility model provides two reference electrodes, which are respectively inserted into the through hole of the winding core and the outer periphery of the winding core and led out of the shell through the perforated portion, thereby avoiding the problem of damage to the electrode piece caused by opening the cylindrical winding core when installing the reference electrode, simplifying the installation method of the cylindrical reference electrode, and installing the internal and external reference electrodes to coordinate the reference data, ensuring that the electrode potential data of the positive and negative electrodes of the battery are accurate and effective.

[0018] (2) The present invention utilizes the stable potential between the positive and negative electrodes of the reference electrode to monitor the electrode potential of the lithium-plated copper foil negative electrode in the reference electrode, thereby promptly detecting electrode failure and avoiding data distortion.

[0019] (3) The utility model can replenish lithium to the lithium-plated copper foil negative electrode in time during multiple charge and discharge long cycle tests, so as to stably regenerate the negative electrode and ensure that the long cycle test is carried out stably and accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 A partial perspective view of a cylindrical battery of the present invention;

[0022] Figure 2 A partial perspective view of the winding core of the present invention;

[0023] Figure 3 It is a top view of the winding core of the present invention.

[0024] In the figure: 1. Shell; 2. Top cover; 21. Perforated portion; 201. Through hole; 3. Winding core; 301. Through hole; 4. Glue stick; 5. First reference electrode; 51. Negative electrode sheet; 52. Positive electrode sheet; 53. Diaphragm; 6. Second reference electrode. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] like Figure 1 As shown, combined Figure 2 and Figure 3 The utility model discloses a cylindrical battery with an in-situ reference electrode, comprising a shell 1, a top cover 2, a winding core 3, a glue stick 4, a first reference electrode 5 and a second reference electrode 6.

[0027] The shell 1 is cylindrical with an opening on the top, and the winding core 3 is placed in through the top opening.

[0028] The top cover 2 is arranged on the top of the housing 1. Two perforated portions 21 are arranged at intervals on the top cover 2. The top cover 2 is connected to the housing 1 by welding.

[0029] The winding core 3 is disposed in the housing 1 and has a through hole 301 at the center.

[0030] The glue stick 4 is inserted into the through hole 301. The glue stick 4 has insulating properties.

[0031] One end of the first reference electrode 5 is inserted into the through hole 301 and is clamped between the outer wall of the glue stick 4 and the inner wall of the through hole 301, and the other end extends toward the top cover 2. One end of the second reference electrode 6 is tightly attached to the outer circumference of the winding core 3, and the other end extends toward the top cover 2; the first reference electrode 5 and the second reference electrode 6 respectively extend outward through the two perforated portions 21 and are led out of the shell 1. Since the two reference electrodes are respectively inserted into the through hole 301 and attached to the outer circumference of the winding core 3, there is no need to open the rolled-up electrode portion of the winding core 3 when installing the two reference electrodes, which will not cause damage to the winding core 3, and also reduces the difficulty of installing the reference electrodes.

[0032] exist Figure 2 In a preferred embodiment shown, the first reference electrode 5 and the second reference electrode 6 both include a negative electrode sheet 51 , a positive electrode sheet 52 and a separator 53 .

[0033] Among them, the negative electrode sheet 51 is tightly attached to the outer surface of the glue stick 4 or the winding core 3, and is inserted into the through hole 301 through the glue stick 4. This is not only more convenient to operate, but also the first reference electrode 5 is clamped by the glue stick 4 and the inner wall of the winding core 3 to prevent it from moving in the through hole 301.

[0034] The negative electrode sheet 51, the diaphragm 53, the positive electrode sheet 52 and another diaphragm 53 are arranged from the inside to the outside and adhere to each other to form the first reference electrode 5 or the second reference electrode 6. The diaphragm 53 plays the role of insulation to prevent short circuit; each perforated portion 21 is provided with two through holes 201, and the free ends of the negative electrode sheet 51 and the positive electrode sheet 52 extend outward through the two through holes 201 respectively and are led out of the shell 1.

[0035] exist Figure 2 In a preferred embodiment shown, the negative electrode sheet 51 is made of copper foil, and the positive electrode sheet 52 is made of aluminum foil. The above materials are common materials for preparing positive and negative electrode sheets.

[0036] exist Figure 2 In a preferred embodiment shown, the portions of the negative electrode sheet 51 and the positive electrode sheet 52 extending outward from the winding core 3 are wrapped with adhesive tape to avoid leakage or short circuit problems.

[0037] exist Figure 2In a preferred embodiment shown, the length of the portion of the negative electrode sheet 51 wrapped with tape along its extension direction is greater than the length of the portion of the positive electrode sheet 52 wrapped with tape along its extension direction, which helps to form a voltage difference between the positive electrode sheet 52 and the negative electrode sheet 51 in the electrolyte inside the shell 1.

[0038] exist Figure 2 In a preferred embodiment shown, the separator 53 covers the portions of the negative electrode sheet 51 and the positive electrode sheet 52 that are not wrapped with tape, so that the separator 53 can more effectively play the role of insulation and preventing short circuits.

[0039] exist Figure 2 In a preferred embodiment shown, the area of ​​the negative electrode sheet 51 covered by the diaphragm 53 is larger than the area of ​​the portion of the negative electrode sheet 51 not wrapped with tape, and the area of ​​the positive electrode sheet 52 covered by the diaphragm 53 is larger than the area of ​​the portion of the positive electrode sheet 52 not wrapped with tape, so that the diaphragm 53 can fully block the negative electrode sheet 51 and the positive electrode sheet 52.

[0040] exist Figure 2 In a preferred embodiment shown, a positive electrode material is coated on the surface of the positive electrode sheet 52 facing the negative electrode sheet 51 to achieve a positive electrode electrolysis reaction of the positive electrode sheet 52 .

[0041] exist Figure 2 In a preferred embodiment shown, the positive electrode material is lithium iron phosphate slurry, which is a conventional electrode material.

[0042] exist Figure 2 In a preferred embodiment shown, after the first reference electrode 5 and the second reference electrode 6 pass through the perforated portion 21 and are led out of the housing 1 , structural adhesive is applied to the outer surface of the perforated portion 21 and the through hole 201 is sealed to prevent leakage.

[0043] like Figure 1 As shown, combined Figure 2 and Figure 3 , the operating steps of the utility model are:

[0044] After obtaining the normally wound cylindrical core 2 and before welding the current collecting disk, the first reference electrode 5 and the second reference electrode 6 are fixedly mounted on the core 2. The specific steps are as follows:

[0045] 1) Preparation of the electrodes and diaphragms of the two reference electrodes: The negative electrode sheet 51 is made of copper foil with a layer of tape wrapped around its upper half; the positive electrode sheet 52 is made of aluminum foil, coated with lithium iron phosphate slurry on one side, and a layer of tape wrapped around its upper half; the width of the aluminum foil is smaller than that of the copper foil, and the height of the part not wrapped by the tape is also smaller than that of the copper foil; the height of the diaphragm 53 is greater than the height of the part of the copper foil not wrapped by the tape.

[0046] 2) Installation of the first reference electrode 5: The negative electrode sheet 51, the diaphragm 53 and the positive electrode sheet 52 are stacked in sequence on the outer peripheral surface of the rubber stick 4 from the inside to the outside, wherein the side of the positive electrode sheet 52 coated with the lithium iron phosphate slurry faces the negative electrode sheet 51, and then the diaphragm 53 is wrapped around the outside of the positive electrode sheet 52 so that the negative electrode sheet 51, the diaphragm 53 and the positive electrode sheet 52 are tightly attached to each other on the rubber stick 4. At this time, the first reference electrode 5 is obtained, and then it is inserted into the through hole 301 of the winding core 3.

[0047] 3) Installation of the second reference electrode 6: Similarly, the negative electrode sheet 51, the separator 53 and the positive electrode sheet 52 are stacked in sequence from the inside to the outside on the outer peripheral surface of the winding core 3, and a winding core including the first reference electrode 5 and the second reference electrode 6 is obtained.

[0048] 4) After the reference electrode is installed, the winding core 3 is placed into the shell, the current collecting disk and the cover plate are welded, and the free ends of the positive and negative pole pieces of each reference electrode (i.e., the end wrapped by the tape) are led out through the through hole 201 of the perforated portion 21 on the cover plate 2. Then, the current collecting disk is welded to the tabs on the winding core 3, and the cover plate 2 is welded to the periphery of the shell 1, and the through hole 201 on the perforated portion 21 is sealed with structural adhesive, and finally the assembled cylindrical battery is obtained.

[0049] 5) The above cylindrical batteries are subjected to helium inspection and short-circuit test, baking, and liquid injection. During formation, the positive and negative poles of the charge and discharge tester are respectively connected to the positive and negative poles of the cylindrical battery and the positive and negative poles of the two reference electrodes, and a low current of 0.02C is charged for 1 hour. Then, the cylindrical batteries only need to be subjected to routine aging and capacity separation before testing.

[0050] 6) When conducting tests, other short-term tests and long-cycle tests, use voltage monitoring equipment to connect the positive and negative electrodes of the cylindrical battery and the positive and negative plates of the two reference electrodes to obtain their respective relative voltage values. The voltage stability of the lithium-plated copper foil of the reference electrode, based on the stable voltage platform of lithium iron phosphate, can be fed back through the relative voltage value of the aluminum foil. During the long-cycle test, if the voltage of the reference electrode changes abnormally, the lithium-plated copper foil of the reference electrode has failed and can be re-plated with lithium by charging with a small current.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A cylindrical battery with an in-situ reference electrode, characterized in that: include: The housing (1) has an opening at the top; A top cover (2) is provided on the top of the housing (1); A winding core (3) is arranged in the housing (1) and has a through hole (301) at the center; A glue stick (4) is inserted into the through hole (301); a first reference electrode (5), one end of which is inserted into the through hole (301) and sandwiched between the outer wall of the glue stick (4) and the inner wall of the through hole (301), and the other end of which extends toward the top cover (2); a second reference electrode (6), one end of which is in close contact with the outer peripheral surface of the winding core (3) and the other end of which extends toward the top cover (2); Two perforated portions (21) are spaced apart on the top cover (2), and the first reference electrode (5) and the second reference electrode (6) respectively extend outward through the two perforated portions (21) and are led out of the housing (1).

2. The cylindrical battery with an in-situ reference electrode according to claim 1, characterized in that: The first reference electrode (5) and the second reference electrode (6) both include a negative electrode sheet (51), a positive electrode sheet (52) and a diaphragm (53); The negative electrode sheet (51) is tightly attached to the outer peripheral surface of the rubber stick (4) or the winding core (3); the negative electrode sheet (51), the diaphragm (53), the positive electrode sheet (52) and another diaphragm (53) are arranged from the inside out and attached to each other to form a first reference electrode (5) or a second reference electrode (6); Two through holes (201) are provided on each of the perforated portions (21), and the free ends of the negative electrode sheet (51) and the positive electrode sheet (52) respectively extend outward through the two through holes (201) and are led out of the housing (1).

3. The cylindrical battery with an in-situ reference electrode according to claim 2, characterized in that: The negative electrode sheet (51) is made of copper foil, and the positive electrode sheet (52) is made of aluminum foil.

4. The cylindrical battery with an in-situ reference electrode according to claim 2, characterized in that: The portions of the negative electrode sheet (51) and the positive electrode sheet (52) extending outward from the winding core (3) are both wrapped with adhesive tape.

5. The cylindrical battery with an in-situ reference electrode according to claim 4, characterized in that: The length of the portion of the negative electrode sheet (51) wound with the tape along its extension direction is greater than the length of the portion of the positive electrode sheet (52) wound with the tape along its extension direction.

6. The cylindrical battery with an in-situ reference electrode according to claim 4, characterized in that: The diaphragm (53) covers the portions of the negative electrode sheet (51) and the positive electrode sheet (52) that are not wrapped with the tape.

7. The cylindrical battery with an in-situ reference electrode according to claim 6, characterized in that: The area of ​​the negative electrode sheet (51) covered by the diaphragm (53) is larger than the area of ​​the portion of the negative electrode sheet (51) not wrapped with the tape, and the area of ​​the positive electrode sheet (52) covered by the diaphragm (53) is larger than the area of ​​the portion of the positive electrode sheet (52) not wrapped with the tape.

8. The cylindrical battery with an in-situ reference electrode according to claim 3, characterized in that: A positive electrode material is coated on the surface of the positive electrode sheet (52) facing the negative electrode sheet (51).

9. The cylindrical battery with an in-situ reference electrode according to claim 8, characterized in that: The positive electrode material is lithium iron phosphate slurry.

10. The cylindrical battery with an in-situ reference electrode according to claim 2, characterized in that: After the first reference electrode (5) and the second reference electrode (6) pass through the perforated portion (21) and are led out of the housing (1), structural adhesive is applied to the outer surface of the perforated portion (21) and the through hole (201) is sealed.

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