CN220063912U - Potential detection device of pole piece - Google Patents

Abstract

The application provides a potential detection device of a pole piece, which comprises a test assembly, an insulating pressing part and a vessel for containing electrolyte, wherein a clamping groove is formed in the inner wall of the vessel, and the insulating pressing part is positioned in the clamping groove and is configured to be pressed on the pole piece when the pole piece is positioned at one side of the inner wall of the vessel facing the clamping groove. The insulating pressing piece is provided with a plurality of detection openings for exposing the pole pieces. The test assembly includes a potential tester and a test probe movably disposed relative to the insulating press, the potential tester being located outside the vessel and configured to be electrically connectable to the pole piece. The test probe is provided with a detection piece which can be communicated with the pole piece, and the detection piece is positioned in the vessel and is electrically connected with the potential tester so as to penetrate through the detection port or be positioned outside the detection port when the test probe moves relative to the insulating pressing piece. The potential detection device provided by the application can finely characterize the potential difference of the pole piece on at least partial areas, so that the uniformity of the surface of the pole piece is determined.

Description

Potential detection device of pole piece

Technical Field

The application relates to the technical field of batteries, in particular to a potential detection device for pole pieces.

Background

The secondary battery (Rechargeable battery) is also called a rechargeable battery or a storage battery, and is a battery that can be continuously used by activating an active material by charging after discharging the battery.

Secondary batteries are widely used in people's work and daily life due to their chargeable characteristics. The battery cell is used as an electric storage part in the secondary battery, and is usually prepared by adopting a pole piece winding or lamination mode, and the quality of the battery cell directly determines the quality of the secondary battery. Part of the reasons for the failure of the battery cells are the uneven distribution of the general potential on the surface of the pole piece caused by the uneven surface of the pole piece. Currently, the method for representing the uniformity of the surface of the pole piece is usually the representation method of the uniformity of the surface density and the representation method of a scanning electron microscope.

However, these characterization methods cannot characterize the subtle differences in potential over a large area of the pole piece.

Disclosure of Invention

The utility model provides a pole piece potential detection device which can finely characterize potential differences of pole pieces on at least partial areas so as to determine the uniformity of the surfaces of the pole pieces.

The utility model provides a potential detection device of a pole piece, which comprises a test assembly, an insulating pressing part and a vessel for containing electrolyte, wherein a clamping groove is formed in the inner wall of the vessel; the insulating pressing piece is provided with a plurality of detection ports exposing the pole piece;

The test assembly comprises a potential tester and a test probe which is arranged in a movable way relative to the insulating pressing piece, wherein the potential tester is positioned outside the vessel and is configured to be electrically connected with the pole piece; the test probe is provided with a detection piece which can be communicated with the pole piece, and the detection piece is positioned in the vessel and is electrically connected with the potential tester, so that the test probe penetrates through the detection port or is positioned outside the detection port when moving relative to the insulating pressing piece.

In some alternative embodiments, the test probe further comprises a reference electrode located within the vessel and disposed in isolation from the detection member;

the potentiometric test meter is configured to be selectively electrically connected to one of the pole piece and the reference electrode.

In some alternative embodiments, the test probe comprises an insulating fixture, the vessel is provided with a liquid injection port, the insulating fixture is penetrated in the vessel through the liquid injection port, and the detection part and the reference electrode are positioned at the same end of the insulating fixture.

In some optional embodiments, the detection member is a guide pin, and the head of the guide pin is in contact with the surface of the pole piece, or the head of the guide pin is penetrated inside the pole piece.

In some alternative embodiments, the test assembly further comprises a driver located outside the vessel, the driver being coupled to the test probe and configured to drive the test probe to move relative to the insulating press.

In some alternative embodiments, the driver is a stepper motor.

In some alternative embodiments, the test assembly further comprises a pressure sensor located on the test probe and electrically connected to the driver and configured to detect a contact pressure of the test probe with the pole piece.

In some optional embodiments, the clamping groove includes a first clamping groove and two second clamping grooves that are mutually communicated, the first clamping groove is clamped at the bottom end of the insulating pressing member, and the two second clamping grooves are positioned at two sides of the first clamping groove and clamped at two sides of the insulating pressing member.

In some alternative embodiments, the insulating press-fit piece covers the surface of the pole piece.

In some alternative embodiments, the detection port has an opening size greater than or equal to 0.2mm and less than or equal to 3mm, and the distance between adjacent detection ports is greater than or equal to 1mm and less than or equal to 500mm;

And/or, the plurality of detection ports are arranged in an array on the insulating pressing piece.

The application provides a potential detection device for a pole piece, which is characterized in that through a vessel, a clamping groove on the inner wall of the vessel and the arrangement of an insulating pressing piece, the insulating pressing piece and the pole piece are fixed in the clamping groove, and meanwhile, the surface of the pole piece can be ensured to have better flatness through the pressing arrangement of the insulating pressing piece, so that the potentials of different areas on the pole piece can be detected. Through the arrangement of the vessel, the permeation time of the electrolyte in the pole piece can be reduced, so that the problem that the electrolyte does not completely permeate in the pole piece and influences the accuracy of the detection of the potential of the pole piece is avoided. Through setting up of detecting the mouth on the insulating pressfitting, potential tester and the testing probe in the testing probe to when the testing probe removes relative insulating pressfitting, the testing piece can wear to locate the mouth and contact with the pole piece, thereby through the potential tester test pole piece in the electric potential that corresponds this mouth department of detecting. And through the movement arrangement of the plurality of detection ports and the test probes, the detection parts can be sequentially penetrated in the detection ports through the repeated movement of the test probes relative to the insulating pressing part, and the electric potentials of the pole piece at the positions corresponding to the plurality of detection ports are tested through the electric potential tester, so that the electric potentials of at least part of the area of the pole piece are obtained, the electric potential difference of the pole piece at the at least part of the area is represented according to the electric potentials, and the uniformity of the surface of the pole piece is determined.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort to a person skilled in the art.

Fig. 1 is a schematic structural diagram of a potential detection device for pole pieces according to an embodiment of the present application;

fig. 2 is a schematic view of the assembly of pole pieces and insulating presswork on the inner wall of a vessel.

Reference numerals illustrate:

100-potential detecting means; 1-a vessel; 11-a vessel body; 111-a liquid injection port; 112-a liquid outlet; 12-enclosing piece; 121-enclosing section; 13-clamping grooves; 131-a first clamping groove; 132-a second card slot; 14-a liquid discharge pipe;

2-insulating pressing pieces; 21-a detection port; 3-a test assembly; 31-potential tester;

32-a test probe; 321-detecting piece; 3211-head; 3212-tail; 322-a reference electrode; 323-insulating fixing piece;

33-a driver; 34-a pressure sensor;

200-pole piece.

Detailed Description

Secondary batteries are widely used in people's work and daily life due to their chargeable characteristics. For example, the secondary battery may be applied to a 3C product, an electric vehicle, and the like. The 3C product may include, but is not limited to, electronic products such as cell phones, computers, and the like. Accordingly, the secondary battery in the 3C product may also be referred to as a 3C battery. Secondary batteries are generally classified into lithium ion batteries, sodium ion batteries, zinc ion batteries, and the like according to the materials of the positive electrodes.

Currently, the cells in secondary batteries are generally prepared by winding or laminating the pole pieces. The pole piece in the electric core can be divided into a positive pole piece and a negative pole piece, wherein the positive pole piece can be used for forming the positive pole of the secondary electric core, and the negative pole piece can be used for forming the negative pole of the secondary electric core. The battery cell failure may seriously affect the use of the secondary battery. The uneven surface of the pole piece can cause the failure of the battery core. The uneven surface of the pole piece mainly refers to uneven distribution of potential on the surface of the pole piece, and when the surface of the pole piece is uneven, the potential of the surface of the pole piece in each area has certain difference.

The method for representing the uniformity of the pole piece in the prior art mainly comprises an area density uniformity representation method and a scanning electron microscope representation method. In the scanning electron microscopic characterization mode, the uniformity of the material and the conductive agent in a small range of the pole piece is mainly observed through a scanning electron microscope. The two characterization modes can not characterize the subtle difference on the large area of the surface of the pole piece, and because the size of the pole piece is generally larger, the potential difference of the pole piece in different areas before and after charging and discharging is caused to be less easy to characterize.

Thus, there is a need for an apparatus that can characterize pole piece uniformity.

In the related art, a testing method for testing the surface polarization of a pole piece is provided, in the testing method, a plurality of detection areas are preset on the pole piece, a preset volume of electrolyte is placed in the detection areas, a preset diaphragm is placed above the electrolyte, a reference electrode with a preset size is placed on the diaphragm, one binding post of a voltmeter is connected to the pole piece, the other binding post is connected to the reference electrode, so that open-circuit voltage between the pole piece and the reference electrode in each detection area is detected through the voltmeter, the situation of pole piece polarization distribution is obtained, and the uniformity of the pole piece is characterized.

However, the testing method in the related art is relatively simple, and although the potential difference of different positions of the pole piece can be tested, the electrolyte can volatilize in the testing process, so that the contact between the reference electrode and the pole piece is poor to influence the measurement accuracy, and a certain time is required for the electrolyte to permeate in the pole piece. If the electrolyte is not completely permeated, the test is inaccurate. In addition, the size and the number of the detection areas are limited, so that the test method cannot carry out large-area fine scanning on the pole piece, only partial points on the pole piece can be tested, and the characterization of the uniformity of the pole piece is poor in fineness.

In view of the above, the present application provides a potential detection device for a pole piece, by which a potential difference of the pole piece over at least a partial area can be characterized, so as to determine uniformity of a pole piece surface.

The potential detecting device is further described below with reference to the drawings and embodiments.

Referring to fig. 1, the potential detecting device 100 includes a testing assembly 3, an insulating pressing member 2, and a vessel 1 containing an electrolyte. Wherein, the inner wall of the vessel 1 is provided with a clamping groove 13, the insulating pressing piece 2 is positioned in the clamping groove 13 and is configured to be pressed on the pole piece 200 when the pole piece 200 is positioned at one side of the clamping groove 13 towards the inner wall of the vessel 1. The insulating pressing member 2 has a plurality of detecting openings 21 exposing the pole pieces 200. Like this pole piece 200 and insulating pressfitting piece 2 all can block and establish in draw-in groove 13, fix a position pole piece 200 through draw-in groove 13 and insulating pressfitting piece 2, when fixing pole piece 200 in household utensils 1, establish through the pressure of insulating pressfitting piece 2 and can ensure that the surface of pole piece 200 has better roughness to different regional potential detection on the pole piece 200.

The test assembly 3 comprises a potentiometric tester 31 and a test probe 32, which is arranged movable relative to the insulating press 2, the potentiometric tester 31 being located outside the vessel 1 and being configured to be electrically connectable with the pole piece 200. The test probe 32 has a detecting element 321 capable of conducting with the pole piece 200, and the detecting element 321 is located in the vessel 1 and is electrically connected with the potential tester 31, so as to penetrate through the detecting port 21 or be located outside the detecting port 21 when the test probe 32 moves relative to the insulating pressing member 2.

Because the test probe 32 is movably disposed relative to the insulating pressing member 2, when one of the measurement points of the pole piece 200 needs to be tested, the test probe 32 can move relative to the insulating pressing member 2, so that the detecting member 321 can be disposed in the detecting opening 21 exposing the measurement point and contact with the pole piece 200. Thus, when the pole piece 200 is electrically connected with the potential tester 31, the pole piece 200 can serve as a potential zero point, and electrolyte is used for conducting ions of the pole piece 200 at a measuring point and the potential zero point ions so as to test the potential of the pole piece 200 at the measuring point through the potential tester 31.

Accordingly, when another measurement point of the pole piece 200 needs to be tested, the test probe 32 may first move relative to the insulating pressing member 2, so that the detecting member 321 is located outside the previous detection port 21, then at the next detection port 21 moving to the insulating pressing member 2, the another measurement point is exposed at the next detection port 21, and finally, through the movement of the test probe 32, the detecting member 321 is penetrated in the next detection port 21 and contacts with the pole piece 200, so that the potential of the pole piece 200 at the another measurement point is tested by the potential tester 31.

Through limiting the number, opening size, spacing or arrangement mode of the detection openings 21, and the like, and through the multiple movements of the test probes 32 relative to the insulating pressing member 2, the detection members 321 can sequentially penetrate through the detection openings 21, large-area fine scanning is performed on the pole piece 200, and the potential of the measurement points exposed in the detection openings 21 by the pole piece 200 is sequentially tested through the potential tester 31, so that potential distribution on at least part of the area of the pole piece 200 is obtained, and the potential difference of the pole piece 200 on at least part of the area is finely characterized according to the potential distribution, so that the uniformity of the surface of the pole piece 200 is determined.

Compared with the related art, the application can provide a relatively airtight containing environment for the electrolyte through the arrangement of the vessel 1, which is beneficial to reducing volatilization of the electrolyte, and the electrode slice 200 is soaked in the electrolyte as the electrolyte is injected completely through the electrode slice 200, so that the electrolyte can infiltrate the electrode slice 200 better, and the problem that the electrolyte is not fully infiltrated in the electrode slice 200 to influence the accuracy of potential detection of the electrode slice 200 is avoided.

It should be noted that, the surface of the pole piece 200 may have a plurality of partial areas, and each partial area may include a plurality of measurement points. Therefore, the application not only can finely characterize the potential difference of the pole piece 200 on at least partial areas to determine the uniformity of the surface of the pole piece 200, but also has higher accuracy of potential detection.

The potentiometric tester 31 may be a multimeter or other test device that can be used to measure voltage. The sensing element 321 may be a guide pin. The guide pin can be made of metal which is resistant to electrolyte and is not easy to generate oxidation reduction, for example, the guide pin can be made of steel, nickel, silver, platinum and the like. Alternatively, the lead may be made of a corresponding current collector, for example, a lithium ion secondary battery, and may be made of aluminum when testing the positive electrode sheet of the secondary battery, and copper when testing the negative electrode sheet of the secondary battery.

In some embodiments, the head portion 3211 (tip portion) of the lead may contact the surface of the pole piece 200 to measure the potential distribution of the surface of the pole piece 200 after being electrically connected to the potential tester 31.

Alternatively, in some embodiments, the head portion 3211 of the lead may also be disposed through the interior of the pole piece 200, so that after the lead is electrically connected to the potential tester 31, the lead is used to measure the potential distribution of the bulk phase of the pole piece 200 (the interior of the pole piece 200). The structure of the lead is different compared to the case of measuring the potential distribution of the surface of the pole piece 200. For example, the pins may need to be of different lengths and be thin to facilitate insertion into the interior of pole piece 200, and the surface of the area of the pin where head 3211 contacts the interior of pole piece 200 may need to be insulated to ensure that the pin is only head 3211 contacts the interior of pole piece 200. It should be noted that, the selection of the length of the guide pin depends on the test depth in the pole piece 200, and guide pins with different lengths may be used according to the test depth.

The structure of the potential detecting device 100 of the present application will be further described below by taking the contact of the head portion 3211 of the lead with the surface of the pole piece 200 as an example.

Referring to fig. 1, the vessel 1 may include a vessel body 11, the vessel body 11 having a cavity for containing an electrolyte, the vessel body 11 further having a liquid injection port 111 and a closable liquid discharge port 112, the liquid injection port 111 and the liquid discharge port 112 being located at opposite sides of the vessel body 11 and both communicating with the cavity so as to inject the electrolyte into the cavity from the liquid injection port 111 or so as to facilitate the electrolyte in the cavity to be discharged to the outside of the vessel 1 through the liquid discharge port 112.

The drain port 112 may be used for draining the cleaning liquid during the cleaning of the dish 1. As shown in fig. 1, the liquid injection port 111 may be located at the top of the vessel body 11, and the liquid discharge port 112 may be located at the bottom of the vessel body 11 for injection and discharge of the electrolyte. When the pole piece 200 is tested, the liquid drain 112 is in a closed state so as to store electrolyte, and after the pole piece 200 is tested, the liquid drain 112 is in an open state so as to drain electrolyte or cleaning liquid. Specifically, the vessel 1 may be connected to the drain port 112 with a stopper or a closable drain pipe 14 so as to control the open or closed state of the drain port 112 by the stopper or the drain pipe 14.

The potential detecting device 100 further includes a sealing member (not shown) detachably covering the liquid filling port 111, so that the liquid filling port 111 can be sealed by the sealing member after the electrolyte is filled into the vessel 1, thereby providing a relatively airtight containing environment for the electrolyte and reducing volatilization of the electrolyte. The seal may include, but is not limited to, being a relatively flexible electrolyte-resistant film.

In some embodiments, the potential detecting device 100 may be used without sealing in a glove box or a drying room. If the electrolyte is an aqueous electrolyte, the potential detecting device 100 can be used in the external environment. In the present application, the environment in which the potential detecting device 100 is used is not further limited.

Referring to fig. 1, the vessel 1 may further include a corrosion-resistant enclosure member 12, where the enclosure member 12 may be enclosed on an inner wall of one side of the vessel body 11, so as to enclose a clamping groove 13 with the inner wall of the vessel body 11, so as to facilitate the clamping of the pole piece 200 and the insulating pressing member 2.

Wherein, the vessel body 11 and the enclosing member 12 can be made of glass or other corrosion resistant materials. The enclosure 12 may be integrally formed on the vessel body 11, or may be formed on the vessel body 11 in other ways. In the present application, the materials of manufacture and the connection of the vessel body 11 and the enclosure 12 are not further limited.

Referring to fig. 2, the clamping groove 13 includes a first clamping groove 131 and two second clamping grooves 132 which are mutually communicated, the first clamping groove 131 is clamped at the bottom end of the insulating pressing member 2, the two second clamping grooves 132 are positioned at two sides of the first clamping groove 131 and clamped at two sides of the insulating pressing member 2, so that different sides of the insulating pressing member 2 and the pole piece 200 are clamped through the first clamping groove 131 and the two second clamping grooves 132, and the insulating pressing member 2 and the pole piece 200 are fixed on the inner wall of the vessel body 11.

Referring to fig. 2, the enclosing member 12 may include three enclosing sections 121, and the three enclosing sections 121 may be sequentially connected and distributed at different positions on the inner wall of the vessel body 11, and enclose a first clamping groove 131 and two second clamping grooves 132 with the vessel body 11 respectively. The length of the enclosing section 121 is greater than the length or width of the insulating pressing member 2, so that the bottom end and the edges of both sides of the insulating pressing member 2 are clamped in the clamping groove 13. The length direction of the insulating pressing member 2 may be referred to the Y direction in fig. 2, and the width direction of the insulating pressing member 2 may be referred to the X direction in fig. 2.

The manner in which the insulating press-fit 2 and pole piece 200 are secured to the left inner wall of the vessel body 11 is illustrated in fig. 1 and 2, but does not constitute a limitation of the position of the clamping groove 13. In some embodiments, the clamping groove 13 may also be formed on the right inner wall or inner bottom wall of the vessel 1.

The structure of the potential detecting device 100 will be further described below taking the example that the insulating pressing member 2 is located on the left inner wall of the vessel body 11.

Referring to fig. 1 and 2, the insulating pressing member 2 covers the surface of the pole piece 200, so as to ensure that the surface of the pole piece 200 has good flatness in different areas, and meanwhile, the pole piece 200 has measurement points exposed to the detection port 21 in each partial area for detecting the potential of the pole piece 200 in the partial area. When the detecting pieces 321 are sequentially inserted into the detecting ports 21 and contact the pole piece 200, the potential difference of the pole piece 200 in all regions can be finely represented by the potential tester 31. Alternatively, in some embodiments, when only the potential difference of the local area of the pole piece 200 needs to be characterized, the detecting member 321 is only penetrating through part of the detecting openings 21 and contacts the pole piece 200, so that the potential difference of the pole piece 200 in the local area is finely characterized by the potential tester 31.

The perpendicular projection of pole piece 200 onto insulating press-fit element 2 may be located within insulating press-fit element 2 so that insulating press-fit element 2 may completely cover and press-fit against the surface of pole piece 200. Wherein the dimensions (e.g., length and width) of pole piece 200 are less than or equal to the dimensions of insulating press-fit 2. The dimensions of pole piece 200 and insulating laminate 2 each include a length and a width. In the present application, the dimensions of the pole piece 200 and the insulating pressing member 2 are not further limited, and it is only necessary to ensure that the insulating pressing member 2 can completely cover the surface of the pole piece 200.

The insulating pressing member 2 has a planar structure parallel to the surface of the pole piece 200, so that the insulating pressing member 2 has a good pressing effect on the pole piece 200. The insulating pressing member 2 is prepared from an electrolyte corrosion resistant organic polymer, and the organic polymer is an insulating material. For example, the organic polymer may include, but is not limited to, polyethylene, polypropylene, polyimide, and the like. Generally, the thickness of the insulating pressing member 2 may be greater than or equal to 0.1mm and less than or equal to 2mm, so that the insulating pressing member 2 has better rigidity, so that when the insulating pressing member 2 is pressed on the pole piece 200, the pole piece 200 can maintain better flatness.

Referring to fig. 2, a plurality of detection ports 21 are arranged in an array on the insulating pressing member 2. For example, the plurality of detection ports 21 are arranged in a rectangular array on the insulating pressing member 2, and the insulating pressing member 2 can be regarded as an insulating gate. Through the array arrangement of the detection ports 21, the arrangement of the detection ports 21 and the measurement points of the pole pieces 200 in each partial area can be uniform, so that the representation degree of the potential difference of the pole pieces 200 in each partial area is uniform, and meanwhile, the movement of the test probes 32 can be controlled conveniently.

It should be noted that, in other embodiments, the plurality of detecting ports 21 may be arranged in a non-array manner on the insulating pressing member 2. For example, the arrangement of the detection ports 21 in a partial region on the insulating bonding member 2 may be denser, and the arrangement of the detection ports 21 in another partial region on the insulating bonding member 2 may be sparser. In practical application, the arrangement of the plurality of detection ports 21 can be adjusted according to the characterization requirement of the potential difference of the pole piece 200, and in the application, the arrangement of the plurality of detection ports 21 is not further limited.

The structure of the potential detecting device 100 of the present application will be further described below by taking a rectangular array arrangement of a plurality of detecting ports 21 as an example.

The detection port 21 may include, but is not limited to, a quadrangular hole, a pentagonal hole, a circular hole, and the like. The detection port 21 may be a micro-hole with an opening size of a micrometer scale. The opening size of the detection port 21 may include, but is not limited to, a side length or an inner diameter of the detection port 21, and the like. For example, when the detection port 21 is a quadrangular hole, the opening size of the detection port 21 may be the side length of the quadrangular hole, and when the detection port 21 is a circular hole, the opening size of the detection port 21 may be the inner diameter of the circular hole.

To facilitate fine characterization of the potential difference of pole piece 200 over at least a portion of the area, in some embodiments, the opening size of detection port 21 may be greater than or equal to 0.2mm and less than or equal to 3mm, with the spacing of adjacent detection ports 21 being greater than or equal to 1mm and less than or equal to 500mm. Illustratively, the opening size of the detection port 21 may be 1mm, 1.5mm, 2mm, 2.5mm, or the like, and the pitch of the adjacent detection ports 21 may be 2mm, 5mm, 10mm, 15mm, 20mm, or the like. In this way, the opening size of the detection opening 21 and the interval between adjacent detection openings 21 can be correspondingly adjusted within the above range, so as to change the density degree of the measurement points on the pole piece 200, thereby realizing the fine characterization of different degrees of the potential difference of the pole piece 200 in at least partial areas.

For example, when the opening size of the detection opening 21 is unchanged, if the voltage difference of the pole piece 200 in different partial areas needs to be more finely represented, the distance between adjacent detection openings 21 can be reduced, so that the arrangement of the detection openings 21 is denser, and the electric potential of the pole piece 200 at the measurement point corresponding to each detection opening 21 is sequentially tested by the test assembly 3, so that the fineness of the voltage difference of the pole piece 200 in different partial areas can meet the requirement.

The detecting element 321 may be a micro-lead (abbreviated as micro-lead), the head portion 3211 of the micro-lead may have a diameter greater than or equal to 10 μm and less than or equal to 1000 μm, the tail portion 3212 of the micro-lead may have a diameter greater than or equal to 1mm and less than or equal to 3mm, and the length L of the micro-lead may be greater than or equal to 2mm and less than or equal to 20mm, so that the head portion 3211 of the detecting element 321 may be disposed in the detecting opening 21 in a penetrating manner and contact with the pole piece 200 for detecting the potential of the pole piece 200.

Referring to fig. 1, in some embodiments, the test probe 32 further includes a reference electrode 322, the reference electrode 322 being located within the vessel 1 and disposed in isolation from the detector 321. Potentiometric tester 31 is configured to be selectively electrically connected to one of pole piece 200 and reference electrode 322. Thus, when the reference electrode 322 is electrically connected with the potential tester 31, the reference electrode 322 can also be used as a potential zero point of a measuring point of the pole piece 200 for testing the potential of each measuring point of the pole piece 200, so that the distance between the reference electrode 322 and the detecting piece 321 is constant while the selection of the potential zero point of the measuring point is more diversified, and the relative position or distance between the reference electrode 322 and the measuring point of the pole piece 200 is prevented from influencing the accuracy of the potential test.

When the reference electrode 322 is used as the potential zero point, the electrode sheet 200 is not connected to the potential tester 31. Accordingly, when pole piece 200 is used as a potential zero point, reference electrode 322 is not connected to potential tester 31.

The reference electrode 322, the pole piece 200 and the detecting member 321 may be electrically connected to the potentiometric device 31 through respective wires. Specifically, one end of the wire may pass through the liquid injection port 111 to electrically connect the reference electrode 322, the pole piece 200, and the detecting member 321 with the potentiometric tester 31.

The reference electrode 322 may be a common electrode such as silver or platinum, or may be made of other materials. When the secondary battery is a lithium ion secondary battery, the reference electrode 322 may be made of lithium, when the secondary battery is a sodium ion battery, the reference electrode 322 may be made of sodium, and when the secondary battery is a zinc ion battery, the reference electrode 322 may be made of zinc. The shape of the reference electrode 322 can include, but is not limited to, a disk or a block. In the present application, the material and shape of the reference electrode 322 are not further limited.

Referring to fig. 1, the test probe 32 further includes an insulating fixing member 323, a liquid injection port 111 for electrolyte on the vessel 1, the insulating fixing member 323 is penetrated in the vessel 1 through the liquid injection port 111, and the detecting member 321 and the reference electrode 322 are located at the same end of the insulating fixing member 323, so that the detecting member 321 and the reference electrode 322 can be assembled in the vessel 1 through the insulating fixing member 323, and meanwhile, the insulating arrangement of the detecting member 321 and the reference electrode 322 can be realized through the arrangement of the insulating fixing member 323, so as to ensure that no conduction exists between the reference electrode 322 and the detecting member 321.

The insulation fixture 323 may include, but is not limited to, an insulation rod. The insulating rod may be made of an insulating material resistant to corrosion by an electrolyte, and specific reference may be made to the above description of the material for manufacturing the insulating pressing member 2, which is not described herein.

Referring to fig. 1, the test assembly 3 further comprises a driver 33 located outside the vessel 1, the driver 33 being connected to the test probes 32 and configured to drive the test probes 32 to move relative to the insulating pressing member 2, so that the test probes 32 can be driven to be fixed relative to the insulating pressing member 2 under the control of the driver 33, so that the detecting members 321 of the test probes 32 can be inserted into the plurality of detecting ports 21.

Specifically, the driver 33 may be connected to an end of the insulating fixing member 323 located outside the vessel 1, so that the driver 33 can drive the test probe 32 to move relative to the insulating pressing member 2 by driving the insulating fixing member 323 while fixing the test probe 32 in the vessel 1.

In some embodiments, the driver 33 may be a stepper motor or other device capable of controlling movement of the insulated fixture 323. Through step motor's setting, can carry out the fine control to the relative insulating pressfitting piece 2's of detecting piece 321 travel distance to and detecting piece 321 is at the removal interval of two adjacent detection mouths 21, in order to ensure that detecting piece 321 can accurately wear to establish in detecting mouths 21, and make the distance between detecting piece 321 and the insulating pressfitting piece 2 relatively fixed, when avoiding the electrode to regard as the potential zero point, the relative position or the distance of detecting piece 321 and the measuring point of electrode are not fixed and influence the accuracy of potential test.

It should be noted that, since the vessel 1 is made of the corrosion-resistant glass vessel 1, the vessel 1 has better light transmittance, and in some embodiments, the movement of the test probe 32 relative to the insulating pressing member 2 may also be controlled manually.

The structure of the potential detecting device 100 of the present application will be further described below by taking the example that the driver 33 controls the movement of the test probe 32.

If the test method described in the related art is used to detect the open circuit voltage between the pole piece 200 and the reference electrode 322 in each detection area, the voltage of the probe contacting the pole piece 200 of the multimeter is not limited when the open circuit voltage is detected, so that different people or the same person can use different voltage to test the electric potential, and the accuracy of the open circuit voltage test is affected.

To this end, in some embodiments, referring to fig. 1, the test assembly 3 may further include a pressure sensor 34, where the pressure sensor 34 may be located on the test probe 32 and electrically connected to the driver 33 and configured to detect a contact pressure of the test probe 32 with the pole piece 200, so that when the pressure sensor 34 detects that the contact pressure exceeds a preset value, the driver 33 may control the test probe 32 to face a side of the insulating pressing member 2 away from the pole piece 200 to reduce the contact pressure of the detecting member 321 with the pole piece 200, so that the contact pressure of the test probe 32 with the pole piece 200 is located at the preset value. Alternatively, when the pressure sensor 34 detects that the contact pressure does not reach the preset value, the driver 33 may control the test probe 32 to move towards one side of the pole piece 200 relative to the insulating pressing member 2, so as to increase the contact pressure between the detecting member 321 and the pole piece 200, so that the contact pressure between the test probe 32 and the pole piece 200 is at the preset value.

Through the arrangement of the pressure sensor 34 and the driver 33, the contact pressure between the test probe 32 and the pole piece 200 can be always at a preset value and is relatively fixed, so that the accurate measurement of the potential of the pole piece 200 at each measuring point is realized, and the more accurate potential distribution condition of the pole piece 200 is obtained.

The range of the preset value may include, but is not limited to, 1Mpa to 100Mpa. Different preset values may be set for different materials of pole piece 200. Taking graphite material as an example of the negative electrode sheet of the secondary battery, since the graphite material is soft and has good conductivity, a small contact pressure is required, and the preset value can be set at 1MPa to 50MPa. The positive electrode material adopted by the positive electrode plate of the secondary battery has poor conductivity and is harder, and the preset value can be set between 10MPa and 100MPa. If other materials can be set according to different materials, the preset value is not further limited in the application.

Wherein the pressure sensor 34 may be provided on an end of the insulating fixture 323 located outside the vessel 1 to avoid that the electrolyte affects the normal use of the pressure sensor 34. Specifically, the pressure sensor 34 may be fastened to the insulating fixing member 323 by means of a snap fit, a fastening member, or the like, so as to facilitate the detachment of the pressure sensor 34.

The test procedure was as follows:

when the potential detecting device 100 tests the pole piece 200, the pole piece 200 is firstly required to be installed in the clamping groove 13, the lead of the pole piece 200 is led out from the liquid injection port 111, then the insulating pressing piece 2 is installed in the clamping groove 13 and is pressed on the surface of the pole piece 200, then electrolyte is injected, the detecting piece 321 and the reference electrode 322 are installed on the insulating fixing piece 323 and are arranged in the vessel 1, the detecting piece 321 is electrically connected with the potential tester 31, the potential tester 31 is electrically connected with the pole piece 200 or the reference electrode 322, finally the test probe 32 is controlled to move, so that the detecting piece 321 sequentially contacts the pole piece 200 exposed in each test port, data on the potential tester 31 are read, drawing of the potential map is completed, uniformity or mechanism analysis of the pole piece 200 is judged by combining the drawn potential map, the electrolyte and the pole piece 200 in the vessel 1 are required to be cleaned after the test is finished, and the test probe 32 is required to be maintained.

The test effect of the potential detecting device 100 will be further described with reference to specific examples and comparative examples.

Example 1

And taking out the positive plate and the negative plate after the wound battery cell is fully charged (4.2V) is disassembled, wherein the foil part of the positive plate is welded with a wire, and the wire is led out of the vessel 1. The positive electrode sheet has a length of 400mm and a width of 50mm, wherein the length direction of the electrode sheet 200 can be referred to the above Y direction, and the width direction of the electrode sheet 200 can be referred to the above X direction. The detection opening 21 of the insulating pressing member 2 is square with a side length of 2mm, and the length of the insulating pressing member 2 is greater than 400mm and the width is greater than 50mm, so that the positive plate can be completely covered by the insulating pressing member 2. The pitch of the adjacent two detection ports 21 in the Y direction is 48mm, and the pitch in the X direction is about 3mm. The positive plate is fixed on the left inner wall of the vessel 1 (as shown in fig. 1) by an insulating pressing member 2. The insulating pressing member 2 was 500 μm thick and was made of polyimide.

The detecting piece 321 is an aluminum guide pin, the length of the detecting piece 321 is 10mm, the diameter of the tail portion 3212 is 1mm, and the diameter of the head portion 3211 is 100 mu m. The reference electrode 322 is lithium metal, is mounted on an insulating fixture 323, and is wired to the extraction vessel 1. Electrolyte is injected into the vessel 1 at the injection port 111 so that the level of the electrolyte completely drops beyond the positive electrode sheet.

The contact pressure of 20MPa, which can be converted into a pressure of about 0.23N, is set in the actuator 33 each time, and the running pitch of the stepping motor is set. The walking pitch of the stepping motor in the X direction is 3mm, and the walking pitch in the Y direction is 48mm. The number of measurements of the detecting piece 321 in the X direction was 10 times, the number of measurements in the Y direction was 8 times, and the potentials of the total 80 measurement points were tested. During testing, the lead of the positive plate is electrically connected with the potential tester 31 for the first time, the reference electrode 322 is electrically connected with the potential tester 31 for the second time, and the 80 potential values obtained by the first time testing and the second time testing are respectively drawn into a voltage distribution meter.

Table 1 is a voltage distribution table plotted according to the potential values obtained by the first test in example 1

Table 2 is a voltage distribution table plotted according to the potential values obtained by the second test in example 1

Numbering device	1	2	3	4	5	6	7	8
									1	4.0986	4.0987	4.0992	4.0997	4.0998	4.0995	4.0991	4.0987
2	4.0986	4.0988	4.0992	4.0997	4.0997	4.0995	4.0992	4.0988
									3	4.0987	4.099	4.0992	4.0997	4.0998	4.0994	4.0992	4.0989
4	4.0989	4.099	4.0993	4.0998	4.0999	4.0995	4.0993	4.0989
									5	4.099	4.0991	4.0994	4.1002	4.1	4.0997	4.0992	4.0989
6	4.0989	4.0991	4.0995	4.1	4.1001	4.0997	4.0993	4.0989
									7	4.0988	4.099	4.0994	4.0999	4.0997	4.0996	1.9436	0.2279
8	4.0988	4.0989	4.0994	4.0997	4.0996	4.0994	4.0991	4.0989
									9	4.0987	4.0987	4.0992	4.0995	4.0994	4.0993	4.0991	4.0988
10	4.0986	4.0986	4.0989	4.0992	4.0993	4.0992	4.099	4.0987

The voltage in table 1 and table 2 is expressed in volts (V). From tables 1 and 2, it can be seen that the two points, i.e., the vertical 7 horizontal 7 and the vertical 7 horizontal 8 (the voltage values of the two thickened measurement points) are significantly different from the voltage values of the other measurement points. After checking, the battery cell is disassembled at the position, the battery cell is abnormal, lithium is not embedded into the negative electrode plate at the two measuring points, the negative electrode plate is black, and other parts are golden yellow, so that the potential of the positive electrode plate at the position is lower. As can be seen from tables 1 and 2, the positive electrode sheet has good overall uniformity, but the potentials of the two side edge regions in the X direction and the intermediate region are significantly different, indicating that the positive electrode sheet has more delithiation at the two side edge regions in the X direction and less delithiation at the intermediate region. The voltage distribution correspondence of tables 1 and 2 is good, and there are cases where both side edge regions and the middle region of the positive electrode sheet in the Y direction are similar.

Thus, the potential differences in different regions of the positive electrode sheet and the uniformity of the negative electrode sheet can be finely characterized according to tables 1 and 2.

Example 2

And taking out the positive plate and the negative plate after the battery cells of the lamination are fully charged (4.2V) are disassembled, wherein the foil part of the negative plate is welded with a wire, and the wire is led out of the vessel 1. The length of the negative plate is 50mm and the width is 40mm. The detection opening 21 of the insulating pressing member 2 is square with a side length of 2mm, and the length of the insulating pressing member 2 is larger than 500mm and the width is larger than 40mm, so that the negative plate can be completely covered by the insulating pressing member 2. The pitch of the adjacent two detection ports 21 in both the X direction and the Y direction is 2mm. The negative electrode tab is also fixed to the left inner wall of the vessel 1 by an insulating press 2 (as shown in fig. 1). The thickness and the manufacturing material of the insulating pressing member 2 are the same as those of embodiment 1, and will not be described here again.

The detecting member 321 is a copper guide needle, and the opening size of the detecting member 321, the setting of the reference electrode 322, and the injection amount of the injection port 111 are the same as those of embodiment 1, and will not be described here again. The contact pressure measured each time was set to 10Mpa in the actuator 33, and the running pitch of the stepping motor was set in terms of a pressure of about 0.12N. The walking distance of the stepping motor in the X direction and the Y direction is 2mm. The number of times of measurement of the detecting member 321 in the X direction was 8 times, the number of times of measurement in the Y direction was 12 times, and the potentials of 96 measurement points in total were tested. During testing, the lead of the negative plate is electrically connected with the potential tester 31 for the first time, the reference electrode 322 is electrically connected with the potential tester 31 for the second time, and 96 potential values obtained by the first time testing and the second time testing are respectively drawn into a voltage distribution meter.

Table 3 is a voltage distribution table plotted according to the potential values obtained by the first test in example 2

Numbering device	1	2	3	4	5	6	7	8
									1	0.0008	0.0008	0.0009	0.0008	0.0008	0.0008	0.0009	0.0008
2	0.0007	0.0006	0.0006	0.0007	0.0006	0.0006	0.0007	0.0008
									3	0.0008	0.0006	0.0003	0.0003	0.0004	0.0003	0.0006	0.0008
4	0.0008	0.0006	0.0003	0.0001	0.0001	0.0003	0.0007	0.0009
									5	0.0008	0.0007	0.0003	-0.0002	-0.0002	0.0003	0.0006	0.0008
6	0.0008	0.0006	0.0003	-0.0003	-0.0003	0.0003	0.0007	0.0008
									7	0.0007	0.0006	0.0003	-0.0002	-0.0003	0.0003	0.0006	0.0009
8	0.0008	0.0006	0.0003	-0.0001	-0.0001	0.0003	0.0006	0.0008
									9	0.0008	0.0006	0.0004	0.0002	0.0002	0.0004	0.0006	0.0008
10	0.0008	0.0006	0.0004	0.0004	0.0004	0.0004	0.0006	0.0008
									11	0.0009	0.0007	0.0007	0.0007	0.0007	0.0008	0.0007	0.0009
12	0.0009	0.0009	0.0009	0.001	0.0009	0.001	0.0009	0.0009

Table 4 is a voltage distribution table plotted according to the potential values obtained by the second test in example 2

Numbering device	1	2	3	4	5	6	7	8
									1	0.0477	0.0477	0.0478	0.0479	0.0478	0.0479	0.0479	0.0479
2	0.0477	0.0477	0.0476	0.0477	0.0476	0.0476	0.0477	0.0479
									3	0.0478	0.0476	0.0473	0.0473	0.0474	0.0473	0.0476	0.0478
4	0.0477	0.0477	0.0474	0.047	0.0471	0.0474	0.0477	0.0479
									5	0.0478	0.0476	0.0473	0.0468	0.0468	0.0473	0.0477	0.0478
6	0.0478	0.0476	0.0474	0.0467	0.0467	0.0473	0.0476	0.0478
									7	0.0478	0.0476	0.0473	0.0467	0.0468	0.0474	0.0476	0.0478
8	0.0477	0.0477	0.0473	0.0469	0.0469	0.0473	0.0476	0.0479
									9	0.0478	0.0476	0.0474	0.0473	0.0472	0.0474	0.0477	0.0478
10	0.0477	0.0476	0.0474	0.0474	0.0474	0.0474	0.0477	0.0479
									11	0.0479	0.0478	0.0477	0.0477	0.0477	0.0478	0.0477	0.0479
12	0.0479	0.0479	0.0479	0.048	0.0479	0.048	0.0479	0.0479

The voltage units in tables 3 and 4 are also in volts (V). It can be seen from both the above tables 3 and 4 that the potential of the negative electrode sheet of the laminated battery cell is small in the middle region and large in the peripheral edge region, because the edge region of the negative electrode sheet is wider than the positive electrode sheet, so that the lithium ions have diffusion behavior, and the lithium intercalation of the edge region of the negative electrode sheet is less than that of the middle region and the potential is large. The potential differences in different regions of the negative electrode sheet can be finely characterized according to tables 3 and 4.

Comparative example

And (3) taking out the positive plate and the negative plate after the battery cells of the lamination are fully charged (4.2V) are disassembled, and taking the positive plate for testing. The lithium sheet was attached to the negative electrode of a multimeter as reference electrode 322. And paving a diaphragm on the surface of the positive plate, wherein the lithium plate is positioned on the diaphragm, and the diaphragm is used for separating the lithium plate from the positive plate. Electrolyte is dripped on the diaphragm for ionic conduction, the probe of the universal meter is used for testing the potentials of different positions of the positive plate, and three points are respectively tested according to the top, the middle and the bottom of the positive plate in the Y direction during testing, and the test results are shown in the following table.

Table 5 shows voltage distribution tables plotted in comparative examples

Numbering device	1	2	3
				1	4.0892	4.0573	4.0824
2	4.0768	4.0489	4.0785
				3	4.0672	4.0451	4.0659

The voltage in table 5 is also in volts (V). The comparative example cannot finely feed back the potential distribution of the whole positive plate due to inflexibility of the probe and unfixed test position.

It can be seen that the potential detecting device 100 of the present application can finely characterize the potential difference of at least a partial region of the pole piece 200 and the uniformity of the pole piece 200.

The potential detection device 100 of the present application is suitable for potential testing and uniformity characterization of pole pieces 200 of all wound or laminated cells, which may include, but are not limited to, cells that are lithium ion batteries, sodium ion batteries, other metal ion batteries, or organic batteries. The electrode plate 200 to be tested can be charged after charging and discharging, if the secondary battery is a lithium ion battery, the potential detection device 100 Of the application can study the lithium intercalation uniformity Of the negative electrode plate under different States Of Charge (SOC), and can also study the lithium deintercalation uniformity Of the positive electrode plate, or the lithium deintercalation uniformity after battery circulation, and prohibit the electrode plate 200 Of the battery core without charging and discharging from being used for testing.

In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the drawings are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element in question must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application.

In the description of the present application, it should be understood that the terms "comprises" and "comprising," and any variations thereof, as used herein, are intended to cover a non-exclusive inclusion, such that a process, method, display structure, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed or inherent to such process, method, article, or apparatus.

Unless specifically stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally formed; can be directly connected or indirectly connected through an intermediate medium, and can lead the interior of two elements to be communicated or lead the two elements to be in interaction relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the application.

Claims (10)

1. The potential detection device for the pole piece is characterized by comprising a test assembly, an insulating pressing piece and a vessel for containing electrolyte, wherein a clamping groove is formed in the inner wall of the vessel, and the insulating pressing piece is positioned in the clamping groove and is configured to be pressed on the pole piece when the pole piece is positioned in the clamping groove towards one side of the inner wall of the vessel; the insulating pressing piece is provided with a plurality of detection ports exposing the pole piece;

the test assembly comprises a potential tester and a test probe which is arranged in a movable way relative to the insulating pressing piece, wherein the potential tester is positioned outside the vessel and is configured to be electrically connected with the pole piece; the test probe is provided with a detection piece which can be communicated with the pole piece, and the detection piece is positioned in the vessel and is electrically connected with the potential tester, so that the test probe penetrates through the detection port or is positioned outside the detection port when moving relative to the insulating pressing piece.

2. The potential sensing device of claim 1, wherein the test probe further comprises a reference electrode positioned within the vessel and disposed in isolation from the sensing element;

the potentiometric test meter is configured to be selectively electrically connected to one of the pole piece and the reference electrode.

3. The device of claim 2, wherein the test probe comprises an insulating fixture, the vessel has a liquid filling port, the insulating fixture is disposed in the vessel through the liquid filling port, and the detection member and the reference electrode are disposed at the same end of the insulating fixture.

4. The potential detecting device according to claim 1, wherein the detecting member is a lead, and a head of the lead is in contact with a surface of the pole piece, or the head of the lead is penetrated inside the pole piece.

5. The electrical potential testing device of any one of claims 1-4, wherein the testing assembly further comprises a driver located outside the vessel, the driver being coupled to the test probe and configured to drive the test probe to move relative to the insulating press.

6. The potential detecting device according to claim 5, wherein the driver is a stepping motor.

7. The electrical potential testing device of claim 5, wherein the testing assembly further comprises a pressure sensor located on the test probe and electrically connected to the driver and configured to detect a contact pressure of the test probe with the pole piece.

8. The device according to any one of claims 1 to 4, wherein the clamping groove comprises a first clamping groove and two second clamping grooves which are communicated with each other, the first clamping groove is clamped at the bottom end of the insulating pressing member, and the two second clamping grooves are positioned at two sides of the first clamping groove and clamped at two sides of the insulating pressing member.

9. The potential detecting device according to any one of claims 1 to 4, wherein the insulating pressing member covers a surface of the pole piece.

10. The potential detecting device according to any one of claims 1 to 4, wherein an opening size of the detecting port is 0.2mm or more and 3mm or less, and a pitch between adjacent detecting ports is 1mm or more and 500mm or less;

And/or, the plurality of detection ports are arranged in an array on the insulating pressing piece.