CN116581408A - A lithium-ion battery low-temperature charging method, device, equipment and medium - Google Patents

Abstract

The invention relates to a low-temperature charging method, device, equipment and medium for a lithium-ion battery, including: S1, charging the lithium-ion battery with a preset constant power at low temperature; Three-dimensional tomographic image inside the lithium-ion battery; S3. Based on the distribution of lithium in the three-dimensional tomographic image inside the lithium-ion battery, judge whether lithium precipitation occurs under the constant power charging condition. If lithium precipitation does not occur, continue to use the stepped constant power Until the end of charging; S4. If lithium deposition occurs, determine the position of the lithium ion battery, and charge the lithium ion battery by reducing the constant power, and repeat steps S2-S4. The feature of the present invention based on constant power charging is that it can minimize the low-temperature charging time while avoiding the occurrence of lithium deposition at the negative electrode during the low-temperature charging process.

Description

A lithium-ion battery low-temperature charging method, device, equipment and medium

technical field

The invention relates to a lithium-ion battery low-temperature charging method, device, equipment and medium, and relates to the technical field of power battery detection.

Background technique

Lithium-ion batteries are one of the key components of electric vehicles. At present, more and more customers require that lithium-ion batteries can be charged at low temperatures, and the charging time should not be too long. However, lithium-ion batteries using graphite as the negative electrode material can easily lead to lithium precipitation when charged at low temperature, which in turn induces the occurrence of lithium dendrites, which has an impact on battery life and safety. Therefore, avoiding the occurrence of lithium precipitation during charging is of great significance for improving battery life and safety.

At present, low-temperature charging uses low-current charging and disassembly methods to find the charging boundary of the battery at low temperature, but it cannot quickly find the charging and decomposing lithium boundary, and a lot of verification work needs to be repeated. The long verification cycle is not conducive to the development of the battery project.

Contents of the invention

The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, in view of the above problems, the object of the present invention is to provide a lithium-ion battery low-temperature charging method, device, equipment and medium, which can minimize the low-temperature charging time while avoiding the occurrence of lithium deposition at the negative electrode during low-temperature charging.

In order to realize the above-mentioned purpose of the invention, the technical scheme adopted in the present invention is:

In a first aspect, the present invention provides a low-temperature charging method for a lithium-ion battery, comprising:

S1. Under low temperature conditions, use the preset constant power to charge the lithium-ion battery;

S2. Real-time acquisition of three-dimensional tomographic images inside the lithium-ion battery under different steps and constant power during battery charging;

S3. Based on the distribution of lithium in the three-dimensional tomographic image inside the lithium-ion battery, it is judged whether lithium deposition occurs under the condition of constant power charging. If lithium deposition does not occur, continue to use the stepped constant power until the end of charging;

S4. If lithium deposition occurs, determine the position of the lithium ion battery for lithium deposition, and charge the lithium ion battery by reducing the constant power, and repeat steps S2-S4.

Further, the preset constant power is used to charge the lithium-ion battery under the low temperature condition, including:

At a low temperature range of -20°C to 5°C, the lithium-ion battery is charged to the voltage V1 with a constant power of CP ₁ and left for a set time to allow lithium ions to be fully embedded in the negative electrode graphite.

Further, a measurement system is also included, and the measurement system includes a neutron photography measurement system and an X-ray three-dimensional CT measurement system, based on the neutron photography measurement system and the X-ray three-dimensional CT measurement system, real-time Obtain three-dimensional tomographic images inside the battery under different steps of constant power.

Further, during the charging process of the battery, three-dimensional tomographic images inside the lithium-ion battery are acquired in real time under different step constant power (CP ₁ >CP ₂ ...>CP _N , n=1, 2, 3, 4...n), including:

The neutron ray source using the neutron photogrammetry system passes through the lithium-ion battery, and the neutrons transmitted by the lithium-ion battery are emitted to the scintillation screen, and the light emitted by the scintillation screen is focused on the CCD camera to obtain a neutron image inside the lithium-ion battery;

The X-ray source of the X-ray three-dimensional CT measurement system passes through the lithium-ion battery to obtain the CT image of the lithium-ion battery;

The neutron image inside the lithium-ion battery and the CT image of the lithium-ion battery are superimposed and integrated to obtain a three-dimensional tomographic image inside the lithium-ion battery.

Further, based on the distribution of lithium in the three-dimensional tomographic image inside the lithium-ion battery, it is judged whether lithium precipitation occurs in the case of constant power charging, specifically:

When the lithium element appears in the three-dimensional tomographic image inside the lithium-ion battery, it is judged that lithium precipitation occurs under the condition of constant power charging.

Further, until the end of charging means that when the charging of the battery reaches the charging cut-off voltage, the charging is stopped or the charging process is ended after receiving an instruction to end charging.

In the second aspect, the present invention also provides a low-temperature charging device for lithium-ion batteries, including:

The constant power charging unit is configured to charge the lithium-ion battery with a preset constant power at low temperature;

The image acquisition unit is configured to acquire three-dimensional tomographic images inside the lithium-ion battery under different steps of constant power during battery charging;

The lithium analysis judging unit is configured to judge whether lithium analysis occurs under the condition of constant power charging based on the distribution of lithium in the three-dimensional tomographic image inside the battery; Lithium analysis determines the location of lithium ion battery analysis, and reduces the constant power for charging.

In a third aspect, the present invention also provides an electronic device, including: one or more processors, memory and one or more programs, wherein one or more programs are stored in the memory and configured as the one or more Executed by a plurality of processors, the one or more programs include instructions for performing any of the methods.

In a fourth aspect, the present invention also provides a computer-readable storage medium storing one or more programs, the one or more programs including instructions, and the instructions, when executed by a computing device, cause the computing device to execute the any of the above methods.

The present invention has the following characteristics due to the adoption of the above technical scheme:

1. The present invention is based on the characteristics of constant power charging (the charging current is relatively large at low SOC, which saves charging time, and the charging current is reduced at high SOC). occur.

2. The present invention adopts the method of combining neutron radiography and X-ray three-dimensional CT, and the combination of neutron radiography and X-ray three-dimensional CT just overcomes the shortcomings of both sides, and finally forms a clear image to judge whether lithium analysis occurs inside the lithium battery. The ability to realize real-time and non-destructive detection of lithium precipitation distribution during the entire charging process of lithium-ion batteries is of great significance for alleviating battery life attenuation and safety problems caused by lithium precipitation induced by charging. This will further understand the mechanism of lithium-ion battery life attenuation, It is of great significance to develop lithium batteries with long-life performance.

In summary, the present invention can be widely used in charging lithium-ion batteries.

Description of drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiment. The drawings are only for the purpose of illustrating a preferred embodiment and are not to be considered as limiting the invention. Throughout the drawings, the same reference numerals are used to refer to the same parts. In the attached picture:

FIG. 1 is a schematic flowchart of a low-temperature charging method for a lithium-ion battery provided by an embodiment of the present invention.

FIG. 2 is a structural diagram of an electronic device according to an embodiment of the present invention.

Detailed ways

It should be understood that the terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may also be meant to include the plural forms unless the context clearly dictates otherwise. The terms "comprising", "comprising", "containing" and "having" are inclusive and thus indicate the presence of stated features, steps, operations, elements and/or parts but do not exclude the presence or addition of one or Various other features, steps, operations, elements, components, and/or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order described or illustrated, unless an order of performance is specifically indicated. It should also be understood that additional or alternative steps may be used.

Because the traditional analysis and testing method disassembles the battery to observe the battery interface, it cannot quickly find the boundary of charging and analyzing lithium, and the long verification cycle is not conducive to the development of the battery project. The lithium-ion battery low-temperature charging method, device, equipment and medium provided by the present invention include: including: S1, charging the lithium-ion battery with a preset constant power under low temperature conditions; S2, obtaining different step constant power in real time during the battery charging process Next, the three-dimensional tomographic image inside the lithium-ion battery; S3. Based on the distribution of lithium in the three-dimensional tomographic image inside the lithium-ion battery, judge whether lithium precipitation occurs under the constant power charging condition. power until the end of charging; S4. If lithium deposition occurs, determine the location of lithium ion battery deposition, and charge the lithium ion battery by reducing the constant power, and repeat steps S2-S4. Therefore, based on the characteristics of constant power charging, the present invention can minimize the low-temperature charging time while avoiding the occurrence of lithium deposition at the negative electrode in the low-temperature charging process, and adopts the combination of neutron photography technology and X-ray three-dimensional CT to realize lithium-ion battery The real-time and non-destructive detection of lithium precipitation distribution in the whole process is of great significance for mitigating battery life attenuation and safety problems caused by charging-induced lithium precipitation.

Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the invention may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided for more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

Embodiment 1: As shown in Figure 1, the lithium-ion battery low-temperature charging method provided in this embodiment includes:

S1. Under low temperature conditions, the battery is charged to the voltage V1 with a preset constant power.

In this embodiment, the preset constant power is used to charge the battery to the voltage V1 under low temperature conditions, including: charging the lithium-ion battery at a constant power of CP ₁ (for example, a voltage range of 2.0 to 3.65° C. V) Charge to the voltage V1 and set aside for a set time, the purpose is to allow lithium ions to be fully embedded in the negative electrode graphite, and the settling time can be set according to the usage requirements, which is not limited here.

S2. The measurement system is used to acquire the internal three-dimensional tomographic images of the lithium-ion battery under different steps of constant power in real time.

In this embodiment, the constant powers of different steps are CP ₁ , CP ₂ ...CP _N , and CP ₁ >CP ₂ ...>CP _N , N=1, 2, 3, 4...n.

In this embodiment, the measurement system includes a neutron photography measurement system and an X-ray three-dimensional CT measurement system. When the neutron photogrammetry system measures, neutrons are not charged, and can easily penetrate the electron layer and undergo a nuclear reaction with the nucleus. It is more sensitive to some light elements, but not to heavy elements, and lithium metal is just a light element. Neutron photography is easy to observe the distribution of lithium. The X-ray three-dimensional CT measurement system is more sensitive to heavy elements, but not to light elements, and the materials such as positive and negative electrodes belong to heavy elements, which can be identified by X-ray three-dimensional CT. Through neutron photography The measurement system and the X-ray three-dimensional CT measurement system measure the inside of the lithium-ion battery at the same time, and superimpose the images acquired by the two to obtain a three-dimensional tomographic image inside the lithium-ion battery. The specific process includes:

S21. The neutron ray source using the neutron photogrammetry system passes through the lithium-ion battery, and the neutrons interact with the atomic nuclei of the lithium-ion battery. The neutrons transmitted by the lithium-ion battery are emitted to the scintillation screen, and the light emitted by the scintillation screen is emitted by the scintillation screen. The mirror is reflected to the lens and then focused on the CCD camera to obtain a neutron image inside the lithium-ion battery. The incident direction of the neutron ray is perpendicular to the lithium-ion battery, and the imaging area can be 10cm×10cm.

S22. Simultaneously, the X-ray source of the X-ray three-dimensional CT measurement system passes through the lithium-ion battery to obtain a CT image of the lithium-ion battery.

S23. Superimpose the neutron image inside the lithium-ion battery and the CT image of the lithium-ion battery on each other, use image processing software combined with a superposition algorithm to integrate the two, obtain a three-dimensional tomographic image inside the lithium-ion battery, and clearly obtain the distribution of lithium, Among them, Matalab can be used as the image processing software, and the specific process will not be described in detail.

S3. According to the distribution of lithium in the three-dimensional tomographic image inside the battery, it is judged whether lithium precipitation occurs under the condition of constant power charging. If there is no lithium precipitation, continue to charge with CP1 constant power until the charging ends.

In this embodiment, based on the distribution of lithium in the three-dimensional tomographic image inside the lithium-ion battery, it is judged whether lithium precipitation occurs under the condition of constant power charging, specifically: when the lithium element appears in the three-dimensional tomographic image inside the lithium-ion battery, Then it is judged that lithium precipitation occurs under the condition of constant power charging.

In this embodiment, until the end of charging refers to stopping the charging when the charging of the battery reaches the charging cut-off voltage V2 or ending the charging process upon receipt of the charging end command.

S4. If the lithium is analyzed, determine the location of lithium ion battery for lithium ion battery, and reduce the constant power battery to charge with CP ₂ constant power (CP ₂ <CP1), and repeat steps S2-S4.

In this embodiment, according to different positions of lithium ion battery, such as the R angle, large surface, and near the tab of the lithium ion battery, the cause of the lithium ion battery is determined for subsequent process improvement.

The application of the lithium-ion battery low-temperature charging method of the present invention will be described in detail below through specific examples.

In this example, the LiFePO4 lithium battery is charged at a constant power at low temperature for illustration: select three 27Ah LiFePO square lithium-ion batteries; in a low temperature -20°C incubator environment, the lithium-ion battery is first charged with a constant power CP ₁ of 15W Charge to 3.4V, put it on hold for 10 minutes, use the measurement system to obtain the distribution of lithium concentration on the three-dimensional tomographic image of the lithium-ion battery, and judge _whether lithium is deposited inside the lithium-ion battery. It ends at 3.65V, if you do not analyze lithium, continue to charge at 15W constant power until it ends at 3.65V.

Embodiment 2: The above embodiment 1 provides a low-temperature charging method for a lithium-ion battery. Correspondingly, this embodiment provides a low-temperature charging device for a lithium-ion battery. The device provided in this embodiment can implement the low-temperature charging method for a lithium-ion battery in Embodiment 1, and the device can be realized by software, hardware, or a combination of software and hardware. For the convenience of description, when describing this embodiment, functions are divided into various units and described separately. Of course, the functions of each unit can be realized in one or more pieces of software and/or hardware during implementation. For example, the apparatus may include integrated or separate functional modules or functional units to execute corresponding steps in the methods of the first embodiment. Since the device of this embodiment is basically similar to the method embodiment, the description process of this embodiment is relatively simple. For relevant points, please refer to the part of the description of Embodiment 1. The embodiment of the lithium-ion battery low-temperature charging device provided by the present invention is only is indicative.

The lithium-ion battery low-temperature charging device provided in this embodiment includes:

The constant power charging unit is configured to charge the lithium-ion battery with a preset constant power at low temperature;

The image acquisition unit is configured to acquire three-dimensional tomographic images inside the lithium-ion battery under different steps of constant power during battery charging;

The lithium analysis judging unit is configured to judge whether lithium analysis occurs under the condition of constant power charging based on the distribution of lithium in the three-dimensional tomographic image inside the battery; Lithium analysis determines the location of lithium ion battery analysis, and reduces the constant power for charging.

Embodiment 3: This embodiment provides an electronic device corresponding to the lithium-ion battery low-temperature charging method provided in Embodiment 1. The electronic device can be an electronic device used for a client, such as a mobile phone, a notebook computer, a tablet computer, a desktop Computer, etc., to implement the method of Embodiment 1.

As shown in FIG. 2 , the electronic device includes a processor, a memory, a communication interface and a bus, and the processor, the memory and the communication interface are connected through the bus to complete mutual communication. The bus may be an Industry Standard Architecture (ISA, Industry Standard Architecture) bus, a Peripheral Component Interconnect (PCI, Peripheral Component) bus, or an Extended Industry Standard Architecture (EISA, Extended Industry Standard Component) bus, and the like. A computer program that can run on the processor is stored in the memory. When the processor runs the computer program, it executes the method of Embodiment 1. The realization principle and technical effect are similar to those of Embodiment 1, and are not described here. Let me repeat. Those skilled in the art can understand that the structure shown in FIG. 2 is only a block diagram of a part of the structure related to the solution of this application, and does not constitute a limitation on the computing device to which the solution of this application is applied. The specific computing device can be More or fewer components than shown in the figures may be included, or some components may be combined, or have a different arrangement of components.

In a preferred embodiment, the above logic instructions in the memory can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including Several instructions are used to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage media include: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), optical disk and other media that can store program codes.

In a preferred embodiment, the processor may be various types of general purpose processors such as a central processing unit (CPU) and a digital signal processor (DSP), which are not limited herein.

Embodiment 4: This embodiment provides a computer program product. The computer program product may include a computer program stored on a computer-readable storage medium. The computer program includes program instructions. When the program instructions are executed by the computer, the computer can execute the above-mentioned The implementation principle and technical effect of the method provided in Embodiment 1 are similar to those in Embodiment 1, and will not be repeated here.

In a preferred embodiment, a computer-readable storage medium may be a tangible device that holds and stores instructions for use by an instruction execution device, such as, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device , a semiconductor storage device, or any combination of the above. The computer-readable storage medium stores computer program instructions, and the computer program instructions cause the computer to execute the method provided by the first embodiment above.

Each embodiment in this specification is described in a progressive manner, the same and similar parts of each embodiment can be referred to each other, and each embodiment focuses on the differences from other embodiments. In the description of this specification, descriptions referring to the terms "a preferred embodiment", "further", "specifically", "in this embodiment" and the like mean specific features and structures described in conjunction with the embodiment or example , material or feature is included in at least one embodiment or example of the embodiments of this specification. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

The present application is described with reference to flowcharts and/or block diagrams of methods, apparatus (apparatus), and computer program products according to embodiments of the present application. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (10)

1. A method for low temperature charging of a lithium ion battery, comprising:

s1, charging a lithium ion battery by adopting preset constant power under the low temperature condition;

s2, acquiring three-dimensional tomographic images of the interior of the lithium ion battery under different ladder constant power in real time in the battery charging process;

s3, judging whether lithium is separated under the step constant power charging condition based on the distribution condition of lithium in the three-dimensional chromatographic image inside the lithium ion battery, and if the lithium is not separated, continuing to use the step constant power until the charging is finished;

and S4, determining the lithium precipitation position of the lithium ion battery if the lithium precipitation occurs, and charging the lithium ion battery by reducing constant power, and repeating the steps S2-S4.

2. The method for charging a lithium ion battery at a low temperature according to claim 1, wherein the charging the lithium ion battery with a preset constant power at the low temperature comprises:

at the low temperature of-20 ℃ to 5 ℃, the lithium ion battery is controlled to be CP ₁ And (3) charging to a voltage V1 with constant power, and placing for a set time to enable lithium ions to be fully embedded into the negative graphite.

3. The method for low-temperature charging of a lithium ion battery according to claim 1, further comprising a measurement system, wherein the measurement system comprises a neutron photographic measurement system and an X-ray three-dimensional CT measurement system, and three-dimensional tomographic images of the interior of the battery under different step constant power are acquired in real time in the charging process of the lithium ion battery based on the neutron photographic measurement system and the X-ray three-dimensional CT measurement system.

4. The method for low-temperature charging of a lithium ion battery according to claim 3, wherein the step-wise constant-power three-dimensional tomographic images of the interior of the lithium ion battery are obtained in real time during the battery charging process, comprising:

a neutron ray source of a neutron photographic measurement system penetrates through a lithium ion battery, neutrons transmitted by the lithium ion battery are emitted to a scintillation screen, and light emitted by the scintillation screen is focused on a CCD camera to obtain a neutron image in the lithium ion battery;

an X-ray source of an X-ray three-dimensional CT measuring system passes through the lithium ion battery to obtain a CT image of the lithium ion battery;

and superposing and integrating the neutron image in the lithium ion battery and the CT image of the lithium ion battery to obtain a three-dimensional tomographic image in the lithium ion battery.

5. The method for low-temperature charging of a lithium ion battery according to claim 1, wherein the step constant power charging is performed based on a distribution of lithium in a three-dimensional tomographic image of the interior of the lithium ion battery, specifically:

and when the lithium element appears in the three-dimensional chromatographic image inside the lithium ion battery, judging that lithium is separated under the constant-power charging condition.

6. The method according to claim 1, wherein the step of stopping the charging after the battery is charged to the charge cutoff voltage or receiving a charge ending instruction to end the charging process.

7. A lithium ion battery low temperature charging device, comprising:

the constant power charging unit is configured to charge the lithium ion battery with preset constant power under the condition of low temperature;

the image acquisition unit is configured to acquire three-dimensional tomographic images of the interior of the lithium ion battery under different ladder constant power in the battery charging process;

a lithium-out judging unit configured to judge whether or not lithium-out occurs in the constant-power charging condition based on a distribution condition of lithium in the three-dimensional tomographic image of the battery interior; if lithium is not separated, continuing to use the stepped constant power until the charging is finished, if the lithium separation occurs, determining the lithium separation position of the lithium ion battery, and reducing the constant power to charge.

8. The lithium ion battery low-temperature charging device according to claim 7, wherein the process of obtaining the three-dimensional tomographic image of the interior of the lithium ion battery is:

a neutron ray source of a neutron photographic measurement system penetrates through a lithium ion battery, neutrons transmitted by the lithium ion battery are emitted to a scintillation screen, and light emitted by the scintillation screen is focused on a CCD camera to obtain a neutron image in the lithium ion battery;

an X-ray source of an X-ray three-dimensional CT measuring system passes through the lithium ion battery to obtain a CT image of the lithium ion battery;

and superposing and integrating the neutron image in the lithium ion battery and the CT image of the lithium ion battery to obtain a three-dimensional tomographic image in the lithium ion battery.

9. An electronic device, comprising: one or more processors, memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs comprising instructions for performing any of the methods of claims 1-6.

10. A computer readable storage medium storing one or more programs, wherein the one or more programs comprise instructions, which when executed by a computing device, cause the computing device to perform any of the methods of claims 1-6.