CN215869703U

CN215869703U - Lithium ion battery module

Info

Publication number: CN215869703U
Application number: CN202121520039.8U
Authority: CN
Inventors: 赵俊丽; 李庆明; 郝银玲; 常艳; 袁萍萍
Original assignee: Henan Lvdong Energy Technology Co ltd; Henan Lithium Power Source Co Ltd
Current assignee: Henan Lvdong Energy Technology Co ltd; Henan Lithium Power Source Co Ltd
Priority date: 2021-07-06
Filing date: 2021-07-06
Publication date: 2022-02-18
Anticipated expiration: 2031-07-06

Abstract

The utility model discloses a lithium ion battery module which comprises a lithium ion battery parallel unit, a three-electrode lithium ion battery and a control module. The three-electrode lithium ion battery comprises a bipolar lug structure consisting of a reference electrode, a reference electrode lug, an electrode lug and lug glue. The reference electrode comprises a welding end and a coating end coated with niobium-titanium oxide on two sides; one end of a reference electrode lug is welded with the welding end, and the other end of the reference electrode lug and the electrode lug are bonded into a whole through the lug glue; the three-electrode lithium ion battery and the lithium ion battery are connected in parallel to form a parallel unit. The control module can acquire the potentials of the positive terminal, the negative terminal and the reference electrode of the lithium ion battery parallel unit and alarm when the potential difference exceeds a set value. The lithium ion battery module collects and compares the potentials of the anode, the cathode and the reference electrode of the three-electrode lithium ion battery, and gives an alarm when the potentials reach the alarm potential, so that the lithium precipitation of the lithium ion battery is avoided and prevented.

Description

Lithium ion battery module

Technical Field

The utility model belongs to the technical field of lithium ion batteries, and particularly relates to a lithium ion battery module.

Background

Lithium ion batteries are widely used in new energy vehicles due to their characteristics of high energy density, long cycle life, high safety, and the like. As a power source of a new energy automobile, the lithium ion battery still has more problems in practical application. For example, under low temperature conditions, due to the decrease of the ionic and electronic conductivity of the lithium ion battery, the polarization degree is increased during the charging process, and the polarization performance is more obvious due to continuous charging, thereby increasing the possibility of lithium precipitation. The separated lithium dendrites can be accumulated on the surface of the electrode, and the safety performance of the lithium ion battery is seriously threatened. In addition, as the number of cycles increases, a thick SEI film is formed on the surface of the negative electrode, and the rate performance of the battery is also reduced, and lithium precipitation may occur in the anode when the battery is charged and discharged by using the current used before, thereby affecting the safety performance and the service life of the lithium ion battery.

In the prior art, the lithium analysis in the charging process is lack of monitoring when the lithium ion battery is used, and the lithium ion battery has the risk of lithium analysis in the using process, so that the safety and the service life of the battery are influenced.

SUMMERY OF THE UTILITY MODEL

The purpose of the utility model is: the utility model provides a lithium ion battery module can effectively monitor the charging of battery module, can effectively prevent to appear separating lithium.

The technical scheme of the utility model is as follows:

a lithium ion battery module comprises a lithium ion battery parallel unit, a three-electrode lithium ion battery and a control module; the three-electrode lithium ion battery comprises a double-lug structure, wherein the double-lug structure consists of a reference electrode, a reference electrode lug, an electrode lug and a lug glue; the reference electrode comprises a coating end and a welding end, wherein the two surfaces of the coating end are coated with niobium titanium oxide, and the welding end is a bare copper sheet; the reference electrode lug is welded with the welding end; the reference electrode lug and the electrode lug are bonded into a whole through the lug glue; the electrode tab is a positive electrode tab or a negative electrode tab; the three-electrode lithium ion battery is connected in parallel in the lithium ion battery parallel unit, the control module comprises a voltage acquisition module and an alarm module, the voltage acquisition module is used for acquiring the potentials of the positive end and the negative end of the lithium ion battery parallel unit and the reference electrode, and the alarm module is used for comparing the potentials of the reference electrode and the positive end or the potentials of the reference electrode and the negative end and giving an alarm when the measured potential difference exceeds a set value.

Preferably, the base body of the reference electrode is T-shaped, the end part of the vertical area of the T-shaped is a coating end, and the transverse area of the T-shaped is a welding end.

Preferably, the width of the coating end is 1-3mm and the length is 5-15 mm.

Preferably, the lithium ion battery parallel units are in a plurality of strings.

The utility model has the beneficial effects that:

the lithium ion battery module is provided with the three-electrode lithium ion battery, the three-electrode lithium ion battery adopts the reference electrode with stable electrode potential and two sides coated with niobium-titanium oxide, the control module acquires and compares the potentials of the anode, the cathode and the reference electrode of the three-electrode lithium ion battery, and alarms when the charging reaches the alarm potential, so that the lithium analysis of the lithium ion battery during the charging is avoided and prevented.

Drawings

Fig. 1 is a schematic diagram illustrating a structure of a lithium ion battery module according to this embodiment 1.

Fig. 2 is a schematic view of a bipolar lug structure.

Fig. 3 is a schematic structural view of the reference electrode.

Fig. 4 is a right side view of fig. 3.

Fig. 5 is a schematic structural diagram of a control module.

Fig. 6 is a schematic diagram illustrating a structure of a lithium ion battery module according to embodiment 2.

In the figure: 1. a first lithium ion battery parallel unit; 11. the first lithium ion battery is connected with the negative electrode of the unit in parallel; 12. the first lithium ion battery is connected with the positive electrode of the unit in parallel; 2. A second lithium ion battery parallel unit; 21. the second lithium ion battery is connected with the positive electrode of the unit in parallel; 22. the first lithium ion battery and the second lithium ion battery are connected in parallel with the unit connection point; 3. a three-electrode lithium ion battery; 31. a reference electrode tab; 32. a reference electrode; 321. coating the end; 322. welding the end; 33. gluing a tab; 34. a negative electrode tab; 4. a control module; 41. a voltage acquisition module; 42. an alarm module; 5. a series plate; 6. a reference electrode conducting bar; 7. a first tab conducting bar; 8. a second tab conducting bar; 9. and a third lug conducting bar.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings.

Example 1

Fig. 1 is a schematic diagram illustrating a structure of a lithium ion battery module according to this embodiment 1. As shown in fig. 1, the lithium ion battery module of this embodiment includes a first lithium ion battery parallel unit 1, a second lithium ion battery parallel unit 2, and a control module 4, which are connected in series, where the first lithium ion battery parallel unit 1 is connected in parallel with a three-electrode lithium ion battery 3, and the three-electrode lithium ion battery 3 includes a dual tab structure. Fig. 2 is a schematic diagram of a bipolar tab structure, and as shown in fig. 2, the bipolar tab structure is composed of a reference electrode 32, a reference electrode tab 31, a negative electrode tab 34 and a tab glue 33. Fig. 3 is a schematic structural view of the reference electrode, and fig. 4 is a right side view of fig. 3. As shown in fig. 2, 3 and 4, the base body of the reference electrode 32 is a copper sheet, the base body of the reference electrode 32 is T-shaped, the end of the vertical region of the T-shape is a coating end 321, and the coating end 321 has a width of 1mm and a length of 5 mm. The transverse region of the T-shape is the weld end 322. The two surfaces of the coating end 321 are coated with niobium titanium oxide, and the welding end 322 is a bare copper sheet; the reference electrode tab 31 is welded with the welding end 322; the reference electrode tab 31 and the negative electrode tab 34 are bonded into a whole through the tab glue 33.

When the three-electrode lithium ion battery 3 is manufactured, the above dual-pole lug structure is manufactured firstly, then the reference electrode 32 is clamped between the positive pole piece and the negative pole piece of the battery core and is separated by the diaphragm, and then the negative pole lug 34 connected with the reference electrode is welded with the negative pole piece of the battery core. In the manufacturing process of the battery, the three-electrode lithium ion battery is assembled by the battery core made of the positive and negative pole pieces and the diaphragm in a lamination or winding mode and the reference electrode 32 through the procedures of tab welding, three-side sealing and the like. The three-electrode lithium ion battery is embedded with lithium before being used, and the steps are as follows: after the battery capacity is adjusted to be half-state electricity, a reference electrode tab 31 is connected with a negative electrode of a power supply, a positive electrode tab of a three-electrode lithium ion battery is connected with a positive electrode of the power supply, and the reference electrode is charged to 100% of SOC by adopting 0.05C current; and then, in the same step, connecting the reference electrode tab 31 with the negative electrode of the power supply, connecting the negative electrode tab of the three-electrode lithium ion battery with the positive electrode of the power supply, and charging the reference electrode to 100% of SOC by adopting 0.05C current. This results in the same degree of lithiation on the front and back sides of the reference electrode 32, achieving a stable potential. Then, the three-electrode lithium ion battery 3 is connected in parallel to the first lithium ion battery parallel unit 1.

The control module 4 includes a voltage collecting module 41 and an alarm module 42, and fig. 5 is a schematic structural diagram of the control module. The voltage acquisition module 41 is configured to acquire potentials of the first lithium ion battery parallel unit negative electrode 11 and the first and second lithium ion battery parallel unit connection points 22, and acquire potentials of the second lithium ion battery parallel unit positive electrode 21 and the reference electrode 32, and the alarm module 42 is configured to compare the potentials of the reference electrode 32 and the first lithium ion battery parallel unit negative electrode 11, and may also compare the potentials of the reference electrode 32 and the first and second lithium ion battery parallel unit connection points 22 (i.e., the potentials of the first lithium ion battery parallel unit positive electrode 12). When the lithium ion battery module of this embodiment is charged, the cathode potential of the first lithium ion battery parallel unit is continuously increased, the anode potential is continuously decreased, and when the alarm module 42 detects that the potential difference between the cathode 11 of the first lithium ion battery parallel unit and the reference electrode 32 exceeds the set value of 1.5V, it indicates that lithium ions in the first lithium ion battery parallel unit are reduced to lithium on the anode surface and separated out, the alarm module 42 gives an alarm, and at this time, the interruption of charging can avoid and prevent the lithium ion battery from separating out lithium. In this embodiment, the charging state of the lithium ion battery in the whole lithium ion battery module in the same charging state can be known by monitoring the charging state of the lithium ion battery in the first lithium ion battery parallel unit 1, and the charging state of the lithium ion battery in the second lithium ion battery parallel unit 2 in the whole battery module can be referred.

In addition, through the voltage data acquired by the voltage acquisition module 41, the voltages at the two ends of the first lithium ion battery parallel unit and the second lithium ion battery parallel unit can be acquired, and the real-time monitoring of lithium ion lithium separation behaviors in the positive pole piece and the negative pole piece can be realized without disassembling.

Example 2

Fig. 6 is a schematic diagram illustrating a structure of a lithium ion battery module according to this embodiment. The difference between this embodiment and embodiment 1 is that a series of lithium ion battery parallel units, i.e., a first lithium ion battery parallel unit 1, is used in this embodiment, and a three-electrode lithium ion battery 3 is connected in parallel in the first lithium ion battery parallel unit 1. In addition, the width of the coating end 321 in the bipolar lug structure of the three-electrode lithium ion battery 3 in the embodiment is 3mm, and the length is 15 mm.

The detection result of one three-electrode lithium ion battery used in one lithium ion battery parallel unit is more precise, but for a lithium ion battery module with a plurality of groups of lithium ion battery parallel units, more three-electrode lithium ion batteries are used, and the structure is slightly more complicated.

The three-electrode lithium ion battery is arranged in the lithium ion battery module, the two sides of the reference electrode in the three-electrode lithium ion battery are coated with niobium-titanium oxide, and the niobium-titanium oxide reference electrode has very stable electrode potential and does not react with electrolyte, so that the long-time cycle performance monitoring of the lithium ion battery can be realized, the influence on the performance of the three-electrode lithium ion battery is small, and the lithium analysis monitoring effect can be well played.

It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. The above-described technical features may be combined with each other as long as they do not conflict with each other. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

Claims

1. A lithium ion battery module is characterized by comprising a lithium ion battery parallel unit, a three-electrode lithium ion battery and a control module; the three-electrode lithium ion battery comprises a double-lug structure, wherein the double-lug structure consists of a reference electrode, a reference electrode lug, an electrode lug and a lug glue;

the reference electrode comprises a coating end and a welding end, wherein the two surfaces of the coating end are coated with niobium titanium oxide, and the welding end is a bare copper sheet; the reference electrode lug is welded with the welding end; the reference electrode lug and the electrode lug are bonded into a whole through the lug glue; the electrode tab is a positive electrode tab or a negative electrode tab; the three-electrode lithium ion battery is connected in parallel in the lithium ion battery parallel unit, the control module comprises a voltage acquisition module and an alarm module, the voltage acquisition module is used for acquiring the potentials of the anode, the cathode and the reference electrode of the lithium ion battery parallel unit, and the alarm module is used for comparing the potentials of the reference electrode and the anode or the potentials of the reference electrode and the cathode and giving an alarm when the measured potential difference exceeds a set value.

2. The lithium ion battery module of claim 1, wherein the base of the reference electrode is T-shaped, the end of the vertical region of the T-shape is a coating end, and the lateral region of the T-shape is a welding end.

3. The lithium ion battery module of claim 2, wherein the coated end has a width of 1-3mm and a length of 5-15 mm.

4. The lithium ion battery module of claim 1, wherein the lithium ion battery parallel cells are in a plurality of strings.