Battery with three-electrode battery cell

Abstract

The utility model provides a battery with a three-electrode battery cell, which comprises a shell, a battery cell arranged in the shell and a metal top cover covering the battery cell, and a pole piece group is arranged in the battery cell; the pole piece group comprises a positive pole piece, a negative pole piece and a reference pole piece, and the reference pole piece is arranged between the positive pole piece and the negative pole piece; a positive pole and a negative pole are arranged on the metal top cover in an insulating manner, the positive pole is electrically connected with the positive pole piece, and the negative pole is electrically connected with the negative pole piece; a reference tab for connecting the bottom of the metal top cover is arranged on the reference pole piece; the positive pole and the metal plate can form a first potential detection loop through the reference pole piece, and the negative pole and the metal plate can form a second potential detection loop through the reference pole piece.

Description

TECHNICAL FIELD

[0001] The utility model relates to power battery technical field, concretely relates to a battery with three electrode core. BACKGROUND

[0002] Common battery is two electrode structure, can only detect positive and negative electrode pressure difference, cannot detect negative electrode potential, and cannot carry out accurate monitoring to lithium precipitation phenomenon that occurs at negative pole, and lithium precipitation phenomenon can produce dendritic lithium element, and lithium element can puncture battery separator and cause safety problem, therefore, usually need to introduce third electrode to detect negative electrode potential.

[0003] Traditional three electrode battery is usually pre -buried copper wire, and copper wire is used as reference electrode piece, one end thereof is located in the battery, and the other end is led out through the hole of the cover plate assembly, and then is sealed, and is made in the mode of sealing treatment. UTILITY MODEL CONTENTS

[0004] The utility model discloses a kind of batteries with three electrode core, reference electrode piece is directly connected cover plate assembly metal top cap bottom, measuring instrument is directly connected metal top cap and carries out potential detection, without leading out reference electrode piece from cover plate assembly, avoid the hole on cover plate assembly, preparation process is simple.

[0005] The utility model discloses a kind of batteries with three electrode core, including shell, the core placed in the shell and the metal top cap covered on the core, the core is provided with pole piece group;The pole piece group includes positive pole piece, negative pole piece and reference electrode piece, the reference electrode piece is arranged between the positive pole piece and the negative pole piece;The metal top cap is provided with positive pole and negative pole insulatively, the positive pole is electrically connected with the positive pole piece, and the negative pole is electrically connected with the negative pole piece;Reference electrode lug for connecting the bottom of the metal top cap is provided on the reference electrode piece;The positive pole can form first potential detection loop with the metal plate through the reference electrode piece, and the negative pole can form second potential detection loop with the metal plate through the reference electrode piece.

[0006] The utility model more preferably technical scheme: the reference electrode lug is welded and fixed in the bottom of the metal top cap.

[0007] The utility model more preferably technical scheme: the reference electrode lug is welded and fixed in the bottom of the metal top cap.

[0008] The utility model more preferably technical scheme: the reference electrode lug is welded and fixed in the bottom of the metal top cap.

[0009] The utility model discloses a preferably technical scheme: the positive pole lug for connecting the positive pole post is arranged on the positive pole piece, the negative pole lug for connecting the negative pole post is arranged on the negative pole piece, the length of the reference lug is greater than the length of the positive pole lug and greater than the length of the negative pole lug.

[0010] The utility model discloses a preferably technical scheme: in the pole piece group, the second diaphragm is arranged between the reference pole piece and the positive pole piece and the negative pole piece, and the first diaphragm is arranged on the outside of the positive pole piece or the negative pole piece.

[0011] The utility model discloses a preferably technical scheme: the area of the reference pole piece is less than the area of the second diaphragm, and the upper and lower ends of the second diaphragm protrude from the reference pole piece.

[0012] The utility model discloses a preferably technical scheme: the electric core is formed by the pole piece group.

[0013] The utility model discloses a preferably technical scheme: the area of the reference pole piece is greater than the area of the positive pole piece, and the area of the reference pole piece is greater than or equal to the area of the negative pole piece.

[0014] The utility model discloses a preferably technical scheme: the thickness of the reference pole piece is 0.1mm-1mm.

[0015] The utility model discloses a battery with a three-electrode electric core has the following beneficial effects:

[0016] 1, the reference pole piece is fixed on the bottom of the metal top cover through the reference lug welding, the positive pole piece connects the positive pole post, the negative pole piece connects the negative pole post, the positive pole post forms the first electric potential detection loop between the reference pole piece and the metal plate, and the positive pole potential is detected, the negative pole post forms the second electric potential detection loop between the reference pole piece and the metal plate, and the negative pole potential is detected, does not need to open the hole on the cover plate assembly, and the battery preparation process is simple, and the integrity and the sealing of the battery can be guaranteed.

[0017] 2, the reference pole piece is in the form of sheet, and the area of the reference pole piece is greater than the area of the positive pole piece and the area of the negative pole piece, so that when the electric core expands during the circulation, the positive pole piece and the negative pole piece are uniformly stressed, and the influence of the reference pole piece on the electric core is reduced.

[0018] 3, the number of reference pole pieces can be increased by arranging multiple pole piece groups, voltage data at different positions can be obtained, and potential detection can be carried out after averaging to improve detection accuracy. DRAWINGS

[0019] The accompanying drawings, which are incorporated into and constitute a part of the specification, illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application. In these drawings, like reference numerals are used to represent similar elements. The drawings in the following description are some embodiments of the present application, rather than all the embodiments. For those skilled in the art, other drawings can be obtained from these drawings without creative labor.

[0020] Figure 1 It is a structural schematic view of the embodiment of the present application.

[0021] Figure 2 It is a structural schematic view of the cover plate assembly in the embodiment of the present application.

[0022] Figure 3 It is a structural schematic view of the cover plate assembly in another view in the embodiment of the present application

[0023] Figure 4 It is a structural schematic view of the battery cell containing a group of pole piece groups in the embodiment of the present application.

[0024] Figure 5 It is a top view of the battery cell in the embodiment of the present application.

[0025] Figure 6 It is a structural schematic view of the battery cell containing two groups of pole piece groups in the embodiment of the present application.

[0026] In the figure: 10, cover plate assembly; 11, metal top cover; 12, positive pole; 13, negative pole; 14, lower plastic plate; 141, connecting hole; 20, pole piece group; 21, positive pole piece; 211, positive pole lug; 22, negative pole piece; 221, negative pole lug; 23, reference pole piece; 231, reference lug; 24, first diaphragm; 25, second diaphragm. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the embodiment of the present application more clear, the technical scheme in the embodiment of the present application will be described clearly and completely below in combination with the drawings in the embodiment of the present application. Obviously, the described embodiment is a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other arbitrarily without conflict.

[0028] Please refer to Figures 1 to 6The application discloses a battery with a three-electrode battery cell, which comprises a shell, a battery cell arranged in the shell and a cover plate assembly 10 arranged on the battery cell, wherein the cover plate assembly 10 comprises a metal top cover 11, the battery cell is arranged with a tab group 20, the tab group 20 comprises a positive electrode tab 21, a negative electrode tab 22, a reference electrode tab 23, a first diaphragm 24 and a second diaphragm 25, the reference electrode tab 23 is arranged between the positive electrode tab 21 and the negative electrode tab 22, the second diaphragm 25 is arranged between the reference electrode tab 23 and the positive electrode tab 21 and between the reference electrode tab 23 and the negative electrode tab 22, and the first diaphragm 24 is arranged on the outer side of the positive electrode tab 21 or the negative electrode tab 22. The tab group 20 can be applied to a rolled battery cell or a stacked battery cell, when the tab group 20 is applied to the rolled battery cell, the first diaphragm 24 can separate the positive electrode tab 21 and the negative electrode tab 22 which are overlapped and rolled, when the tab group 20 is applied to the stacked battery cell, the first diaphragm 24 can separate the positive electrode tab 21 and the negative electrode tab 22 which are adjacent and stacked, so that the positive electrode tab 21 and the negative electrode tab 22 are prevented from being overlapped. The application is described by taking the rolled battery cell as an example.

[0029] The metal top cover 11 is usually an aluminum plate in actual production, the metal top cover 11 is arranged with a positive electrode column 12 and a negative electrode column 13, the positive electrode tab 21 is arranged with a positive electrode lug 211 for connecting the positive electrode column 12, the negative electrode tab 22 is arranged with a negative electrode lug 221 for connecting the negative electrode column 13, and the reference electrode tab 23 is arranged with a reference electrode lug 231 for connecting the metal top cover 11. The positive electrode column 12 penetrates through the metal top cover 11 and is fixed and insulated between the positive electrode column 12 and the metal top cover 11 through a sealing piece, and the negative electrode column 13 penetrates through the metal top cover 11 and is fixed and insulated between the negative electrode column 13 and the metal top cover 11 through a sealing piece.

[0030] The reference electrode lug 231 is welded and fixed at the bottom of the metal top cover 11, the shell is arranged with an electrolyte, the battery cell is immersed in the electrolyte, the first diaphragm and the second diaphragm can separate the tabs and make the ions in the electrolyte pass through, the positive electrode tab 21 can form a potential detection loop with the metal top cover 11 through the reference electrode tab 23, and the negative electrode tab 22 can form a potential detection loop with the metal top cover 11 through the reference electrode tab 23. Specifically, a positive electrode of a measuring instrument is connected to the positive electrode column 12, a negative electrode of the measuring instrument is connected to the metal top cover 11, the positive electrode column 12 forms a first potential detection loop with the metal top cover 11 through the reference electrode tab 23, and a positive electrode potential is measured; a positive electrode of a potential measuring instrument is connected (usually pasted) to the metal top cover 11, a negative electrode of the measuring instrument is connected to the negative electrode column 13, the negative electrode column 13 forms a second potential detection loop with the metal top cover 11 through the reference electrode tab 23, and a negative electrode potential is measured. In the application, since the reference electrode lug 231 is connected to the metal top cover 11 and the reference electrode lug 231 is fixed at the bottom of the metal top cover, the metal top cover 11 does not need to be perforated, and the potential can be measured, so that the sealing property of the battery is ensured.

[0031] Preferably, the connection between the reference tab 231 and the metal top cover 11 is located between the positive pole 12 and the negative pole 13 to separate the reference tab 231 from the positive pole 12 or the negative pole 13. Further, the connection between the reference tab 231 and the metal top cover 11 is adhered with an insulating tape to avoid the reference tab 231 from being mistakenly connected to the positive tab 211 or the negative tab 221, and to avoid the welding area from being in contact with the electrolyte to form a corrosion potential.

[0032] As another embodiment, the non-connection part of the reference tab 231 is coated with an insulating anticorrosion coating to avoid the reference tab 231 from being in contact with the electrolyte to form a corrosion potential and affect the accuracy of the potential test. Specifically, the top part of the reference tab 231 is welded to the bottom of the metal top cover 11, and the rest of the reference tab 231 is coated with an insulating anticorrosion coating.

[0033] The cover plate assembly 10 further comprises a lower plastic plate 14 arranged below the metal top cover 11 to separate the battery cells. The lower plastic plate 14 is provided with a connecting hole 141 through which the reference tab 231 is welded to the bottom of the metal top cover 11. Similarly, the lower plastic plate 14 is provided with two through holes in which the positive pole 12 and the negative pole 13 are arranged, respectively. The positive pole 12 penetrates the lower plastic plate 14 to connect the positive tab 211, and the negative pole 13 penetrates the lower plastic plate 14 to connect the negative tab 221. In this application, the lower plastic plate 14 is an integral plate arranged at the bottom of the metal top cover 11. Alternatively, the lower plastic plate 14 is provided with two plates which are symmetric about the two ends of the metal top cover 11. The two lower plastic plates 14 are provided with through holes to accommodate the positive pole 12 and the negative pole 13, respectively. One of the two lower plastic plates 14 is provided with a connecting hole, and the two lower plastic plates 14 can be bonded and spliced to cover the bottom of the metal top cover 11.

[0034] Since the positive pole 12 and the negative pole 13 both penetrate the metal top cover 11, the bottom of the positive pole 12 and the bottom of the negative pole 13 are located below the metal top cover 11, and the distance between the positive tab 211 and the positive pole 12 is less than the distance between the reference tab 231 and the bottom of the metal top cover 11. Therefore, preferably, the length of the reference tab 231 is greater than the length of the positive tab 211 and greater than the length of the negative tab 221, so as to facilitate the direct welding of the reference tab 231 to the metal top cover 11.

[0035] Preferably, the thickness of the reference tab 23 is 0.1mm-1mm to reduce the occupation of the reference tab 23 in the volume space of the battery cell after the introduction of the reference tab 23, and to reduce the impact on the battery capacity.

[0036] In the lithium battery, the area of the negative electrode tab is greater than that of the positive electrode tab. Therefore, in the tab group 20, the area of the reference tab 23 is greater than that of the positive electrode tab 21, and the area of the reference tab 23 is greater than or equal to the area of the negative electrode tab 22. Taking the positive electrode tab 21 as an example, when the battery expands during the cycle process, the positive electrode tab 21 and the reference tab 23 are in surface contact through the second separator 25, and the contact area is the side surface of the positive electrode tab 21. The positive electrode tab 21 is subjected to the same force everywhere, which can avoid the problem of tab fracture caused by uneven force. The negative electrode tab 22 is the same.

[0037] The areas of the first separator 24 and the second separator 25 are greater than that of the positive electrode tab 21. Specifically, taking the first separator 24 as an example, the upper and lower ends of the first separator 24 exceed the upper and lower ends of the positive electrode tab 21, so as to form a barrier at both ends of the positive electrode tab 21, avoiding the overlap of the positive electrode tab 21 and the negative electrode tab 22.

[0038] The area of the reference tab 23 is less than that of the first separator 24 and less than that of the second separator 25. Specifically, taking the second separator 25 as an example, the upper and lower ends of the second separator 25 exceed the upper and lower ends of the reference tab 23, so as to form a barrier at both ends of the reference tab 23, avoiding the overlap of the reference tab 23 and the positive electrode tab 21, or the overlap of the reference tab 23 and the negative electrode tab 22, which affects the accuracy of the potential test.

[0039] The battery cell can include one or more tab groups 20. In the battery cell including multiple tab groups 20, adjacent tab groups 20 are stacked, there are multiple reference tabs 23, and different reference tabs 23 are located at different positions in the battery cell. Compared with the potential measured by a single reference tab 23 at a single position, arranging the reference tab 23 at different positions in the battery cell can reduce the influence of factors such as uneven electrolyte concentration and uneven internal temperature of the battery cell on potential measurement, thereby improving the accuracy of potential detection. Figure 4 The structure of the battery cell including one tab group 20 is shown in the following figure, Figure 6 The structure of the battery cell including two tab groups 20 is shown in the following figure.

[0040] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not limiting. Although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions described in the foregoing examples can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not change the essence of the corresponding technical solutions beyond the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery with a three-electrode cell, characterized in that, The device includes a housing, a battery cell placed inside the housing, and a metal top cover (11) covering the battery cell. An electrode assembly (20) is disposed inside the battery cell. The electrode assembly (20) includes a positive electrode (21), a negative electrode (22), and a reference electrode (23), with the reference electrode (23) disposed between the positive electrode (21) and the negative electrode (22). A positive electrode post (12) and a negative electrode post are insulatedly disposed on the metal top cover (11), with the positive electrode post connected to the negative electrode post. The electrode plates (21) are electrically connected, and the negative electrode post (13) is electrically connected to the negative electrode plate (22); the reference electrode plate (23) is provided with a reference electrode tab (231) for connecting to the bottom of the metal top cover; the positive electrode post (12) can form a first potential detection circuit with the metal top cover (11) through the reference electrode plate (23), and the negative electrode post (13) can form a second potential detection circuit with the metal top cover (11) through the reference electrode plate (23).

2. A battery with a three-electrode cell according to claim 1, characterized in that, The reference tab (231) is welded and fixed to the bottom of the metal top cover (11).

3. A battery with a three-electrode cell according to claim 2, characterized in that, Insulating tape is provided at the connection between the reference tab (231) and the metal top cover (11).

4. A battery with a three-electrode cell according to claim 2, characterized in that, The bottom of the metal top cover (11) is covered with a lower plastic plate (14).

5. A battery with a three-electrode cell according to claim 2, characterized in that, The positive electrode plate (21) is provided with a positive electrode tab (211) for connecting to the positive electrode post (12), and the negative electrode plate (22) is provided with a negative electrode tab (221) for connecting to the negative electrode post (13). The length of the reference electrode tab (231) is greater than the length of the positive electrode tab (211) and greater than the length of the negative electrode tab (221).

6. A battery with a three-electrode cell according to claim 1, characterized in that, Within the electrode group (20), a second separator (25) is provided between the reference electrode (23), the positive electrode (21), and the negative electrode (22), and a first separator (24) is provided on the outside of the positive electrode (21) or the outside of the negative electrode (22); within the cell, multiple sets of electrode groups (20) are provided, and adjacent electrode groups (20) are separated by the first separator (24).

7. A battery with a three-electrode cell according to claim 6, characterized in that, The area of ​​the reference electrode (23) is smaller than the area of ​​the second diaphragm (25), and the upper and lower ends of the second diaphragm (25) protrude from the reference electrode (23).

8. A battery with a three-electrode cell according to claim 1, characterized in that, The battery cell is formed by stacking or rolling the electrode group (20).

9. A battery with a three-electrode cell according to claim 1, characterized in that, The area of ​​the reference electrode (23) is greater than the area of ​​the positive electrode (21), and the area of ​​the reference electrode (23) is greater than or equal to the area of ​​the negative electrode (22).

10. A battery with a three-electrode cell according to claim 1, characterized in that, The thickness of the reference electrode (23) is 0.1 mm to 1 mm.

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