CN111628210A - Lithium ion battery supporting in-situ measurement of internal temperature of battery and manufacturing method - Google Patents

Abstract

The invention relates to a lithium ion battery supporting in-situ measurement of the internal temperature of the battery and a manufacturing method. The in-situ measurement of the internal temperature of the battery is realized by a thermocouple probe embedded in the battery pole piece, and the battery can be accurately measured during the use of the battery. The high-precision dynamic measurement of the internal temperature change of the battery solves the inherent temperature measurement error problem that is unavoidable in the prior art, and has a significant effect on improving the operation safety of the battery; at the same time, the manufacturing method is simple and easy to implement.

Description

A lithium-ion battery supporting in-situ measurement of the internal temperature of the battery and a manufacturing method thereof

technical field

The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery and a manufacturing method for supporting in-situ measurement of the internal temperature of the battery.

Background technique

At present, the main source of power for the automobile industry is still fossil fuels, and most of the emissions are volatile organic compounds and greenhouse gases. The huge load of the transportation industry has caused the pollution problem to increase year by year, posing great challenges to human health and the environment. Not only that, with the continuous development of social economy and industrial technology level, various other industrial emissions and pollution are also leading to the continuous deterioration of the natural environment, and at the same time, the fossil fuel resources are also constantly decreasing. The problem of deterioration is becoming more and more difficult.

At present, countries around the world have mainly taken two measures in response to the shortage of fossil energy and pollution: one is to change the way of energy dependence, and gradually complete the transition from relying on fossil energy to relying on sustainable energy; the other is to transform transportation The power-driven mode of the transportation industry is changing from the mode of transportation powered by internal combustion engines to the mode of transportation powered by electricity. Among them, electric vehicle (Electric Vehicle) has gradually entered people's field of vision in recent years because of its significant advantages of low energy consumption and low emission, and the development trend is rapid. At the same time, the emission standards of fuel vehicles in various countries are becoming more and more strict, and some countries have put the elimination of traditional fuel vehicles on the agenda. Under this general situation, research on electric vehicle technology has also been carried out. Three-electric technology is the core technology of electric vehicle development, among which power battery system, as the energy storage device of electric vehicle, has always been a research hotspot in various countries. At present, there is still a big gap between electric vehicles and traditional vehicles in terms of power performance, endurance performance and safety performance. In the future, power batteries have great potential in terms of high capacity, high power, and high reliability.

The temperature of the battery will significantly affect the various performance indicators of the battery system. During the working process, the internal electrochemical process will significantly affect the temperature change of the system, which in turn will have an important impact on the output power, efficiency, life and other indicators of the battery, as well as the safety performance. . The battery will face the risk of thermal runaway under high temperature conditions, and the charge and discharge performance will also be significantly reduced under low temperature conditions, so the monitoring of battery temperature is particularly important.

At present, the temperature monitoring of most battery systems adopts the method of setting thermocouples on the surface of the battery shell. Although this temperature measurement method is convenient and low-cost, the temperature measured externally cannot fully reflect the transient temperature field inside the battery. There are inherent errors in temperature, which will directly affect the user's judgment on the safety state of the battery, which may lead to serious consequences such as thermal runaway and explosion of the battery. Not only in the field of electric vehicles, but also in the field of digital equipment, wherever batteries are needed, it is necessary to quickly and accurately measure the battery temperature. Therefore, the industry urgently needs an in-situ method for measuring the internal temperature of a battery with both rapidity and accuracy.

SUMMARY OF THE INVENTION

In order to solve the deficiencies of the prior art, the present invention proposes a lithium-ion battery that supports in-situ measurement of the internal temperature of the battery and a manufacturing method thereof. In situ measurement, so as to more accurately monitor the internal safety state of the battery and avoid serious consequences such as thermal runaway and explosion of the battery.

To achieve the above purpose, the technical scheme adopted in the present invention includes:

A lithium-ion battery that supports in-situ measurement of the internal temperature of the battery, characterized in that it includes at least one thermocouple probe pole piece, and the thermocouple probe pole piece is a positive or negative electrode piece pre-embedded with at least one thermocouple probe. .

Further, the thermocouple probe is a T-type thermocouple or a K-type thermocouple with a wire diameter of less than 100 microns, and the thickness of the pole piece is greater than or equal to 100 microns.

Further, a thermocouple probe is pre-buried at the geometric center position of the pole piece.

Further, more than two thermocouple probes are pre-embedded on the pole piece of the thermocouple probe, and the two or more thermocouple probes are pre-embedded on the pole piece symmetrically with the geometric center of the pole piece.

Further, the thermocouple terminals corresponding to the thermocouple probes are used as measurement terminals for connection to the battery thermal management system, and/or the measurement terminals are connected to an external data acquisition instrument.

A lithium-ion battery manufacturing method supporting in-situ measurement of the internal temperature of the battery, characterized in that it comprises the following steps of preparing a pre-embedded thermocouple probe pole piece:

Fix the thermocouple probe on the current collector, coat the electrode slurry on the current collector fixed with the thermocouple probe, and dry the electrode slurry together with the thermocouple probe;

Or, coat the electrode slurry on the current collector, insert and fix the thermocouple probe before drying the electrode slurry, and dry the electrode slurry and the thermocouple probe together.

Further, when the thickness of the pole piece is 100 to 120 microns, the thermocouple probe is fixed on the current collector, and then the electrode slurry is coated on the current collector with the thermocouple probe fixed, and the electrode slurry is dried together with the thermocouple probe. The pre-embedded thermocouple probe pole piece is prepared by the molding method; when the thickness of the pole piece is greater than 120 microns, the electrode slurry is coated on the current collector, and the thermocouple probe is inserted and fixed before the electrode slurry is dried. The electrode slurry and the thermocouple probe Pre-embedded thermocouple probe pole pieces are prepared by drying and forming together.

Further, the method also includes fixing a thermocouple probe on the current collector corresponding to the geometric center of the pole piece, and then coating the electrode slurry on the current collector on which the thermocouple probe is fixed, and the electrode slurry and the thermocouple probe. Dry and form together;

Or, coat the electrode slurry on the current collector, insert and fix a thermocouple probe at the geometric center position of the corresponding pole piece before the electrode slurry is dried, and the electrode slurry and the thermocouple probe are dried and formed together.

Further, the method also includes fixing two or more thermocouple probes on the current collector corresponding to specific positions of the pole pieces, and then coating the electrode slurry on the current collector on which the thermocouple probes are fixed, and the electrode slurry is connected to the thermocouple probe. The probe is dried and formed together;

Or, coat the electrode slurry on the current collector, insert and fix more than two thermocouple probes at the specific position of the corresponding pole piece before the electrode slurry is dried, and the electrode slurry and the thermocouple probes are dried and formed together.

For example, the method further includes assembling the prepared pre-embedded thermocouple probe pole pieces according to a normal lithium-ion battery production process flow.

The beneficial effects of the present invention are:

At present, the temperature acquisition of the battery system generally uses the method of attaching a thermocouple to the surface of the battery case. Although the method is simple, the dynamic response of the external measurement is slow and cannot reflect the real temperature of the battery. Using the lithium ion battery that supports in-situ measurement of the internal temperature of the battery according to the present invention, the in-situ measurement of the internal temperature of the battery is realized by the thermocouple probe embedded on the battery pole piece, the pole piece of the thermocouple probe is constructed, and only the thermocouple is embedded in advance. The probe, the thermocouple terminal, that is, the measurement terminal is drawn out, and the signal of the thermocouple can be directly detected by an external data acquisition instrument. During the use of the battery, it can accurately and quickly perform high-precision dynamic measurement of the internal temperature of the battery and its rate of change, so as to monitor The internal safety state of the battery solves the inherent temperature measurement error problem that is unavoidable in the prior art, avoids serious consequences such as thermal runaway explosion of the battery, and has a significant effect on improving the operational safety of the battery. The invention also relates to a method for manufacturing a lithium ion battery that supports in-situ measurement of the internal temperature of the battery. It only needs to add a step of pre-embedding a thermocouple probe in the battery pole piece on the basis of the existing manufacturing method of the lithium ion battery to prepare a method for preparing a lithium ion battery. The lithium-ion battery for position measurement is simple and easy to implement; at the same time, the number of embedded thermocouple probes can be selected according to actual needs.

Description of drawings

FIG. 1 is a schematic diagram of a pole piece of a pre-embedded thermocouple probe of the present invention.

FIG. 2 is a schematic diagram of an embodiment of a lithium-ion battery that supports in-situ measurement of the internal temperature of the battery according to the present invention.

Description of the drawing numbers: 1-thermocouple probe pole piece, 11-positive electrode piece, 12-negative electrode piece, 2-thermocouple probe, 21-measurement terminal, 3-diaphragm, 41-aluminum foil, 42-copper foil.

Detailed ways

In order to understand the content of the present invention more clearly, detailed description will be given in conjunction with the accompanying drawings and embodiments.

The invention relates to a lithium ion battery supporting in-situ measurement of the internal temperature of the battery, comprising at least one thermocouple probe pole piece, the thermocouple probe pole piece being a positive or negative electrode piece pre-embedded with at least one thermocouple probe. 1 is a schematic diagram of the pre-embedded thermocouple probe pole piece of the present invention, including a thermocouple probe pole piece 1 and a thermocouple probe 2 embedded in the thermocouple probe pole piece 1. The thermocouple includes a thermocouple probe and a thermocouple Terminal, or probe (ie working end) and free end (ie measuring end), the invention only pre-embeds the thermocouple probe in the pole piece, the thermocouple terminal is not embedded but outside the pole piece, the thermocouple terminal is used as The measurement terminal 21 is connected to the battery thermal management system, and/or the measurement terminal 21 of the thermocouple probe 2 is connected to an external data acquisition instrument. The thermocouple probe 2 (working end) is in contact with the area where the temperature needs to be measured, and the measurement terminal 21 is connected to the corresponding data acquisition device, reads the thermoelectric potential, and obtains the temperature of the measurement point through calculation.

Since the thermocouple probe 2 needs to be buried, the thickness of the thermocouple probe pole piece 1 is preferably greater than or equal to 100 microns, and the thermocouple probe 2 adopts a T-type thermocouple or a K-type thermocouple with a wire diameter of less than 100 microns, so as to reduce the amount of thermoelectricity as much as possible. The influence of the even probe 2 on the normal operation of the pole piece 1 of the thermocouple probe. According to the actual needs of battery temperature measurement, one or more thermocouple probe pole pieces 1 can be pre-embedded in a battery, and one or more thermocouple probes can be pre-embedded on each thermocouple probe pole piece 1. Thermocouple probe 2. When a single thermocouple probe pole piece 1 is pre-embedded with a thermocouple probe 2, preferably the thermocouple probe 2 is pre-buried at the geometric center position of the thermocouple probe pole piece 1; when a single thermocouple probe pole piece 1 is pre-buried When there are more than two thermocouple probes 2, preferably the thermocouple probe 2 is pre-embedded in the thermocouple probe pole piece 1 symmetrically with the geometric center of the thermocouple probe pole piece 1, for example, two are pre-embedded symmetrically up and down with the geometric center of the pole piece. For the thermocouple probe 2, either two thermocouple probes 2 are pre-embedded symmetrically on the left and right of the geometric center of the pole piece, or four thermocouple probes 2 are pre-embedded symmetrically on the top, bottom, left and right on the geometric center of the pole piece.

Figure 2 is a schematic diagram of an embodiment of a lithium-ion battery that supports in-situ measurement of the internal temperature of the battery according to the present invention. This embodiment provides a laboratory-made single-layer soft pack battery, including aluminum foil 41 and copper foil as current collectors 42. The positive thermocouple probe pole piece 11, the negative thermocouple probe pole piece 12 and the diaphragm 3 sandwiched between the positive thermocouple probe pole piece 11 and the negative thermocouple probe pole piece 12, in order to measure the internal temperature of the battery in situ, In this embodiment, the positive thermocouple probe pole piece 11 and the negative thermocouple probe pole piece 12 are each embedded with a thermocouple probe 2 , and the thermocouple terminal corresponding to the thermocouple probe 2 is used as the measurement terminal 21 to connect to the battery thermal management system. Enables in-situ measurement of the internal temperature of the battery. Most of the batteries actually used are multi-layer structures, but the basic principle is exactly the same as that described in this embodiment. The thermocouple probe 2 can be pre-buried in any layer of the positive thermocouple probe pole piece 11 and/or the negative thermocouple as required. Di probe pole piece 12.

The invention also relates to a method for manufacturing a lithium ion battery that supports in-situ measurement of the internal temperature of the battery. Different from the existing method for manufacturing a lithium ion battery, the pre-embedded thermocouple probe pole piece needs to be prepared, that is, the thermocouple probe pole piece 1 needs to be prepared. The thermocouple probe 2 is pre-buried on the top, which specifically includes: fixing the thermocouple probe on the current collector, then coating the electrode slurry on the current collector with the thermocouple probe fixed, and drying the electrode slurry and the thermocouple probe together. , Coat the electrode slurry on the current collector, insert and fix the thermocouple probe before the electrode slurry is dried, and dry the electrode slurry and the thermocouple probe together. The process of pre-embedding the thermocouple probe in the pole piece can be adjusted according to the thickness of the battery pole piece. The method of fixing the thermocouple probe and then smearing can be used, or the method of inserting the thermocouple probe after smearing. The choice of the specific method depends on the thickness of the thermocouple probe pole piece 1 to be fabricated. Preferably, when the thickness of the thermocouple probe pole piece 1 is 100 to 120 microns, the thermocouple probe 2 is fixed on the current collector, and the electrode slurry is The pre-embedded thermocouple probe pole piece is prepared by coating the material on the current collector fixed with the thermocouple probe 2, and the electrode slurry is dried and formed together with the thermocouple probe 2; the thickness of the thermocouple probe pole piece 1 is greater than 120 microns, using The electrode slurry is coated on the current collector, and the thermocouple probe 2 is inserted and fixed before the electrode slurry is dried. , it is preferable to pre-embed the thermocouple probe 2 in the middle of the overall thickness of the thermocouple probe pole piece 1, which can ensure the acquisition accuracy and facilitate the spatial arrangement. Also in order to ensure the acquisition accuracy, when a thermocouple probe 2 is embedded in the thermocouple probe pole piece 1, the thermocouple probe 2 should be fixed at the geometric center of the thermocouple probe pole piece 1; When the number of thermocouple probes 2 is above, two or more thermocouple probes 2 should be fixed on a specific position of the thermocouple probe pole piece 1 , and the specific position is preferably a position symmetrical with the geometric center of the thermocouple probe pole piece 1 . After the pre-embedded thermocouple probe pole piece is prepared, it is assembled according to the normal lithium-ion battery production process to make a lithium-ion battery that supports in-situ measurement of the internal temperature of the battery.

The lithium-ion battery that supports in-situ measurement of the internal temperature of the battery made according to the above method, the thermocouple probe 2 collects the internal temperature of the battery in-situ during use, and the measuring terminal 21 is connected to the corresponding data acquisition device to read the thermoelectric potential, and obtained through calculation. The temperature of the measuring point.

The above is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention. etc. should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (10)

1. The lithium ion battery is characterized by comprising at least one thermocouple probe pole piece, wherein the thermocouple probe pole piece is a positive pole piece or a negative pole piece embedded with at least one thermocouple probe.

2. The lithium ion battery of claim 1, wherein the thermocouple probe is a T-type thermocouple or a K-type thermocouple having a wire diameter of less than 100 microns, and the thickness of the pole piece is 100 microns or greater.

3. The lithium ion battery of claim 2, wherein a thermocouple probe is embedded in the geometric center of the pole piece.

4. The lithium ion battery of claim 2, wherein more than two thermocouple probes are embedded in the thermocouple probe pole piece, and the more than two thermocouple probes are embedded in the pole piece symmetrically with respect to the geometric center of the pole piece.

5. The lithium ion battery of claim 3 or 4, wherein a thermocouple terminal corresponding to the thermocouple probe serves as a measurement terminal for connection to a battery thermal management system and/or the measurement terminal is connected to an external data acquisition instrument.

6. A manufacturing method of a lithium ion battery supporting in-situ measurement of the internal temperature of the battery is characterized by comprising the following steps of:

fixing a thermocouple probe on a current collector, coating electrode slurry on the current collector fixed with the thermocouple probe, and drying and molding the electrode slurry and the thermocouple probe together;

or, coating electrode slurry on the current collector, inserting a fixed thermocouple probe before drying the electrode slurry, and drying and molding the electrode slurry and the thermocouple probe together.

7. The method of claim 6, wherein the thickness of the pole piece is 100 to 120 microns, a thermocouple probe is fixed on a current collector, electrode slurry is coated on the current collector fixed with the thermocouple probe, and the electrode slurry and the thermocouple probe are dried and molded together to prepare an embedded thermocouple probe pole piece; the thickness of the pole piece is more than 120 microns, the embedded thermocouple probe pole piece is prepared by a method of coating electrode slurry on a current collector, inserting a fixed thermocouple probe before the electrode slurry is dried, and drying and molding the electrode slurry and the thermocouple probe together.

8. The method of claim 6,

fixing a thermocouple probe on the current collector corresponding to the geometric center of the pole piece, coating the electrode slurry on the current collector fixed with the thermocouple probe, and drying and molding the electrode slurry and the thermocouple probe together;

or, coating electrode slurry on the current collector, inserting and fixing a thermocouple probe in the geometric center position of the corresponding pole piece before the electrode slurry is dried, and drying and molding the electrode slurry and the thermocouple probe together.

9. The method of claim 6,

fixing more than two thermocouple probes at specific positions on a current collector corresponding to the pole pieces, coating electrode slurry on the current collector fixed with the thermocouple probes, and drying and molding the electrode slurry and the thermocouple probes together;

or, coating electrode slurry on the current collector, inserting and fixing more than two thermocouple probes at specific positions corresponding to the pole pieces before drying the electrode slurry, and drying and molding the electrode slurry and the thermocouple probes together.

10. The method of any one of claims 6 to 9, wherein the prepared pre-embedded thermocouple probe pole pieces are assembled according to a normal lithium ion battery production process flow.

Images