Liquid injection method, detection apparatus, liquid injection system, and manufacturing system for battery cell

Abstract

A liquid injection method, a detection apparatus, a liquid injection system, and a manufacturing system for a battery cell. The liquid injection method can significantly improve the liquid injection efficiency. The liquid injection method comprises: constructing a liquid injection curve on the basis of an acquired liquid injection time and liquid injection amount of a battery sample; dividing the liquid injection curve into at least two segments, such that the average slopes of two adjacent segments of the liquid injection curve are different from each other, and using a connection point of the two adjacent segments of the liquid injection curve as a target time inflection point; calculating liquid injection parameters on the basis of the target time inflection point, wherein the liquid injection parameters comprise the number of liquid injection operations and a liquid injection amount corresponding to each liquid injection operation; and providing an electrolyte to an initial battery on the basis of the liquid injection parameters, and performing resting processing between two adjacent liquid injection operations, so as to obtain a liquid-injected battery. The liquid injection method in the present application can significantly improve the liquid injection efficiency.

Description

Liquid injection method, detection device, liquid injection system and battery monomer manufacturing system

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202311827934.8, filed on December 27, 2023, entitled “Injection method, detection device, injection system and battery cell manufacturing system,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the technical field of battery manufacturing, and in particular to a liquid injection method, a detection device, a liquid injection system, and a battery cell manufacturing system. Background Art

[0004] Batteries are widely used due to their reliable performance, pollution-free operation, and zero memory effect. For example, with increasing attention paid to environmental protection and the growing popularity of new energy vehicles, demand for batteries is expected to surge.

[0005] However, the current battery production efficiency is low, especially the low injection efficiency, which seriously affects the market demand for batteries. Therefore, it is urgent to improve the battery injection efficiency in the battery manufacturing process.

[0006] Summary of the Invention

[0007] The embodiments of the present application provide a liquid injection method, a detection device, a liquid injection system, and a battery cell manufacturing system. The liquid injection method can significantly improve the liquid injection efficiency.

[0008] In a first aspect, an embodiment of the present application provides a liquid injection method, comprising:

[0009] Constructing an injection curve based on the injection time and injection amount of the obtained battery sample;

[0010] Dividing the injection curve into at least two segments so that the average slopes of the two adjacent injection curves are different, and using the connecting point of the two adjacent injection curves as the target time inflection point;

[0011] Calculating injection parameters based on the target time inflection point, the injection parameters include the number of injection operations and the injection volume corresponding to each injection operation;

[0012] The electrolyte is provided to the initial battery according to the injection parameters, and a static treatment is performed between two adjacent injection operations to obtain a liquid-injected battery.

[0013] Therefore, the embodiment of the present application confirms the injection characteristics (injection curve) of the battery sample by obtaining the parameters of the battery sample during the injection process, such as the injection time and injection volume; confirms the target time inflection point that affects the injection efficiency based on the injection curve, thereby confirming the injection parameters of the initial battery, performing injection operations in batches, and reserving a rest treatment time between two adjacent injection operations. During this time interval, the electrolyte can flow into the pores of the positive electrode sheet, the negative electrode sheet and the separator to infiltrate the electrode assembly, and create free space in the initial battery, which is convenient for the next injection after the rest treatment, reduces the injection resistance of the next injection, shortens the injection time of the next injection, and improves the injection efficiency of the next injection, thereby improving the overall injection efficiency and further improving the production efficiency of the battery cell.

[0014] In some embodiments, the steps of providing electrolyte to an initial battery according to injection parameters and performing a static treatment between two adjacent injection operations to obtain an injection battery include:

[0015] Providing a first injection amount of electrolyte to an initial battery to obtain a pre-filled battery, wherein the number of injection operations in the injection parameters is two, and the injection amounts corresponding to the two injection operations are the first injection amount and the second injection amount, respectively;

[0016] statically treating the pre-filled battery to obtain a static battery;

[0017] A second injection amount of electrolyte is provided to the stationary battery to obtain a liquid-injected battery.

[0018] Therefore, the embodiment of the present application can significantly improve the injection efficiency of the second injection process through the above operations, so that the efficiency of a single injection is higher, thereby improving the injection efficiency of the entire injection process.

[0019] In some embodiments, the steps of providing electrolyte to an initial battery according to injection parameters and performing a static treatment between two adjacent injection operations to obtain an injection battery include:

[0020] Providing a first injection amount of electrolyte to an initial battery to obtain a pre-filled battery, wherein the number of injection operations in the injection parameters is three, and the injection amounts corresponding to the three injection operations are the first injection amount, the second injection amount, and the third injection amount, respectively;

[0021] Static treatment of the pre-filled battery to obtain a pre-stabilized battery;

[0022] providing a second injection amount of electrolyte to the pre-stationary battery to obtain a refilled battery;

[0023] resting the refilled battery to obtain a rested battery;

[0024] A third amount of electrolyte is provided to the battery for further resting to obtain a liquid-filled battery.

[0025] Therefore, the embodiment of the present application can significantly improve the injection efficiency of the second injection process and the third injection process through the above operations, so that the efficiency of a single injection is higher, thereby improving the injection efficiency of the entire injection process.

[0026] In some embodiments, the resting time is 0.1 to 10 hours. When the resting time is within the above range, the electrolyte can infiltrate the interior of the electrode assembly, diffuse into the pores of the electrode assembly, and release free space, which is conducive to improving the injection efficiency after the resting time.

[0027] In some embodiments, the temperature of the static treatment is 20° C. to 65° C. When the static treatment temperature is within the above range, the electrolyte can infiltrate the interior of the electrode assembly, diffuse into the pores of the electrode assembly, and release free space, which is conducive to improving the injection efficiency after the static treatment.

[0028] In some embodiments, before providing electrolyte to the initial battery according to the injection parameters and performing a resting process between two adjacent injection operations to obtain the injected battery, the process further includes: vacuuming the initial battery to ensure that the internal pressure of the initial battery meets a preset pressure value. The vacuuming of the initial battery prior to injection provides a certain degree of vacuum inside the initial battery, which facilitates the injection operation.

[0029] In some embodiments, the preset air pressure value (absolute pressure) is 100 Pa to 30,000 Pa.

[0030] In some embodiments, the step of constructing an injection curve based on the injection time and injection volume of the battery sample includes:

[0031] Providing electrolyte to the battery sample;

[0032] Obtaining an initial time of providing the electrolyte and a weight of the battery sample corresponding to the initial time, and obtaining weights of the battery sample corresponding to multiple time points, wherein the multiple time points all occur after the initial time point;

[0033] Calculate the difference between each moment and the initial moment as the injection time, and calculate the difference between the weight corresponding to each moment and the weight corresponding to the initial moment as the injection volume;

[0034] Construct an injection curve based on the injection time and injection volume.

[0035] Therefore, the embodiments of the present application can accurately obtain relevant injection parameters of the battery sample through the above steps, thereby improving the accuracy of injection curve construction.

[0036] In some embodiments, the average slope of one of the two adjacent injection curves is A, and the average slope of the other injection curve is B, wherein 1×10 -6 ≤A / B<1; alternatively, 1×10 -6 ≤A / B≤1×10 -1 By defining the above formula, the injection operation can be performed more accurately in batches, thereby improving the injection efficiency of each single injection.

[0037] In the second aspect, the present application proposes a detection device, which includes a collection component, a receiving component and a liquid injection component. The collection component is configured to obtain multiple moments and the weight of the battery sample corresponding to each moment; the receiving component is arranged on the collection component, and the receiving component includes a receiving cavity having at least one opening, and the receiving cavity is configured to receive the battery sample; the liquid injection component is arranged opposite to the opening, and the liquid injection component is configured to be connected or disconnected with the battery sample.

[0038] Therefore, the detection device according to the embodiment of the present application can accurately obtain relevant injection parameters of the battery sample and improve the accuracy of the injection curve construction.

[0039] In some embodiments, the detection device further includes a bracket assembly, the bracket assembly including a base and a guide member, the base being provided with a collection assembly; the guide member including a support portion and a sliding portion, the support portion being connected to the base, the sliding portion being fixedly connected to the liquid injection assembly, and the sliding portion being connected to the support portion, the sliding portion including a first state and a second state, in which the sliding portion is movably connected to the support portion to drive the liquid injection assembly toward or away from the receiving assembly; in the second state, the sliding portion is locked to the support portion. The guide member can provide guidance for the movement of the liquid injection assembly, thereby improving the movement accuracy of the liquid injection assembly.

[0040] In some embodiments, the support portion extends along a first direction; the receiving assembly and the liquid injection assembly are disposed relative to each other along the first direction. In a first state, the sliding portion is movably connected to the support portion to drive the liquid injection assembly to move along the first direction toward or away from the receiving assembly. The sliding portion drives the liquid injection assembly to move, and the support portion can provide guidance for the movement of the liquid injection assembly, thereby improving the movement accuracy of the liquid injection assembly.

[0041] In some embodiments, the liquid injection component includes a liquid injection piece and an air pressure pipeline, the liquid injection piece includes an injection pipeline and an injection part connected to the liquid injection pipeline, the liquid injection pipeline is configured to be connected to an external electrolyte, and the liquid injection part is configured to be connected to or disconnected from a battery sample; the air pressure pipeline is arranged in the liquid injection part, the air pressure pipeline is configured to be connected to an external air circuit, and the air pressure pipeline is configured to be connected to or disconnected from the battery sample through the liquid injection part.

[0042] In the third aspect, the present application proposes a liquid injection system, which includes a detection device, a control device and an electrolyte providing device of any embodiment of the second aspect of the present application, the control device is configured to calculate the liquid injection parameters based on the time of detection by the detection device and the weight of the battery sample; the electrolyte providing device is configured to provide electrolyte to the initial battery according to the liquid injection parameters.

[0043] In a fourth aspect, the present application proposes a battery cell manufacturing system, which includes the liquid injection system of any embodiment of the third aspect of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0045] FIG1 is a schematic flow chart of a liquid injection method according to an embodiment of the present application;

[0046] FIG2 is a flow chart of step S100 in the liquid injection method provided in one embodiment of the present application;

[0047] FIG3 is a flow chart of step S300 in the liquid injection method provided in one embodiment of the present application;

[0048] FIG4 is a flow chart of step S300 in the liquid injection method provided in another embodiment of the present application;

[0049] FIG5 is a schematic flow chart of a liquid injection method according to another embodiment of the present application;

[0050] FIG6 is a schematic structural diagram of a battery cell manufacturing system according to an embodiment of the present application;

[0051] FIG7 is a schematic structural diagram of a liquid injection system according to an embodiment of the present application;

[0052] FIG8 is a schematic structural diagram of a control device in a liquid injection system according to an embodiment of the present application;

[0053] FIG9 is a schematic structural diagram of a detection device according to an embodiment of the present application;

[0054] FIG10 is a schematic structural diagram of a detection device according to an embodiment of the present application used to detect battery samples.

[0055] The accompanying drawings are described as follows: X, first direction; 1, manufacturing system; 10, liquid injection system; 100, detection device; 110, collection component; 120, accommodating component; 121, accommodating chamber; 122, opening; 130, liquid injection component; 131, liquid injection part; 1311, liquid injection pipeline; 1322, liquid injection part; 132, air pressure pipeline; 140, bracket assembly; 141, base; 142, guide part; 1421, support part; 1422, sliding part; 200, control device; 201, processor; 202, memory; 203, communication interface; 204, communication bus; 300, electrolyte providing device; 2, battery sample. DETAILED DESCRIPTION

[0056] Below, with appropriate reference to the accompanying drawings, the embodiments of the liquid injection method, detection device, liquid injection system, and battery cell manufacturing system of the present application are described in detail. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0057] " Range " disclosed in this application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be inclusive or exclusive of end values, and can be arbitrarily combined, that is, any lower limit can form a range with any upper limit combination. For example, if the range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that the range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3,4 and 5 are listed, then the following ranges can all be expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In this application, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, a numerical range of "0 to 5" indicates that all real numbers between "0 and 5" are listed herein, and "0 to 5" is merely an abbreviation for a combination of these values. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0058] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0059] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0060] Unless otherwise specified, all steps S of the present application may be performed sequentially or randomly, preferably sequentially. For example, a method includes steps S(a) and (b), which means that the method may include steps S(a) and (b) performed sequentially, or may include steps S(b) and (a) performed sequentially. For example, a method may further include step S(c), which means that step S(c) may be added to the method in any order, for example, the method may include steps S(a), (b) and (c), or may include steps S(a), (c) and (b), or may include steps S(c), (a) and (b, etc.

[0061] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the embodiments of the present application.

[0062] In addition, the technical terms "first," "second," etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. In the description of the embodiments of the present application, the meaning of "plurality" is more than two, unless otherwise specifically defined.

[0063] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0064] In the embodiments of the present application, the terms "plurality" and "multiple" refer to two or more.

[0065] In the embodiments of the present application, battery cells may include lithium-ion secondary battery cells, lithium-ion primary battery cells, lithium-sulfur battery cells, sodium-lithium-ion battery cells, sodium-ion battery cells, or magnesium-ion battery cells, etc., and the embodiments of the present application do not limit this. Battery cells may be cylindrical, flat, rectangular, or other shapes, etc., and the embodiments of the present application do not limit this. Battery cells are generally divided into three types based on the packaging method: cylindrical battery cells, prismatic battery cells, and soft-pack battery cells, and the embodiments of the present application do not limit this.

[0066] The battery referred to in the embodiments of this application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery module or a battery pack. A battery generally includes a casing that encloses one or more battery cells. The casing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0067] A battery cell consists of a housing, an electrode assembly, and an electrolyte. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator. A battery cell primarily operates by allowing metal ions to migrate between the positive and negative electrode sheets through the electrolyte.

[0068] The production process of battery cells includes electrode fabrication, assembly, and post-injection processes. The assembly process involves assembling the positive and negative electrode sheets and separators into the shell, followed by the injection of electrolyte into the shell. During this process, the efficiency of electrolyte injection has a significant impact on production efficiency. Electrolyte injection is typically performed in a single injection process (i.e., the electrolyte required for the battery cell is injected into the shell at once). This injection method takes a long time and has poor efficiency, which is not conducive to improving battery cell production efficiency.

[0069] In view of the poor injection efficiency in related technologies, it needs to be further improved. In the embodiment of the present application, by collecting the injection curve generated during one injection process and observing the rules of the injection curve, multiple injections are performed, which can effectively shorten the injection time and improve the injection efficiency.

[0070] The embodiment of the present application proposes a liquid injection method.

[0071] As shown in Figure 1, the injection method includes:

[0072] Step S100, constructing an injection curve based on the obtained injection time and injection volume of the battery sample;

[0073] Step S200, dividing the injection curve into at least two segments so that the average slopes of two adjacent injection curves are different, and taking the connecting point of the two adjacent injection curves as the target time inflection point;

[0074] Step S300, calculating injection parameters according to the target time inflection point, the injection parameters including the number of injection operations and the injection volume corresponding to each injection operation;

[0075] In step S400 , electrolyte is provided to the initial battery according to injection parameters, and a static treatment is performed between two adjacent injection operations to obtain an injected battery cell.

[0076] In the embodiments of this application, a battery sample refers to a battery cell that has not yet been injected with electrolyte; an initial battery refers to a battery cell that has not yet been injected with electrolyte. The battery sample and the initial battery can be battery cells of the same specifications, for example, the battery sample and the initial battery have the same housing dimensions, the same internal electrode assembly parameters, and the same total electrolyte injection volume. The battery sample can be used as a test sample to test injection-related parameters, and based on the test results, an optimal injection solution can be provided for the initial battery injection in actual production.

[0077] The battery sample or initial battery has free space inside, which includes the gap between the shell and the electrode assembly, and the free space may also include the interlayer gap between the positive electrode sheet, the separator, and the negative electrode sheet in the electrode assembly. The free space can accommodate electrolyte. After the electrolyte is injected, the electrolyte is contained in the free space. The electrolyte flow steps are as follows: (1) the electrolyte moves from the space between the shell and the electrode assembly to the inside of the electrode assembly; (2) the electrolyte flows inside the electrode assembly and infiltrates the electrode assembly. The infiltration steps include: (2.1) the electrolyte is transferred in the gap between the positive electrode sheet and the separator under capillary force, and in the gap between the negative electrode sheet and the separator; (2.2) the electrolyte seeps in the pores of the separator; (2.3) the electrolyte diffuses through the separator to the surface of the positive electrode sheet and the negative electrode sheet on both sides and then diffuses into the pores of the positive electrode sheet and the negative electrode sheet. The electrolyte flows at a relatively high speed in step (1). During this process, as the amount of electrolyte injected increases, the free space in the battery sample decreases. Furthermore, due to the presence of the free space, the electrolyte injection resistance is relatively small, resulting in a relatively high injection efficiency. As the amount of electrolyte injected increases, the free space in the battery sample further decreases, resulting in a relatively small space available for accommodating the electrolyte. Furthermore, the electrolyte flows at a relatively slow speed in step (2), resulting in an increased electrolyte injection resistance and a relatively poor injection efficiency.

[0078] In related technologies, the injection volume is usually divided into two parts, for example, one part is 80% of the injection volume (calculated by volume) and the other part is 20% of the injection volume; 80% of the injection volume is pre-injected into the initial battery, and 20% of the injection volume is injected a second time. Although this method also injects liquid in batches, the injection volume division and the injection time interval are not analyzed and tested based on the flow time of the electrolyte in the specific battery cell specifications and the immersion time in the electrode assembly. Therefore, it cannot effectively improve the injection efficiency of the second injection, resulting in a negligible improvement in the overall injection efficiency.

[0079] The embodiment of the present application confirms the injection characteristics (injection curve) of the battery sample by obtaining the parameters of the battery sample during the injection process, such as the injection time and injection volume; confirms the target time inflection point that affects the injection efficiency based on the injection curve, thereby confirming the injection parameters of the initial battery, performing injection operations in batches, and reserving a rest treatment time between two adjacent injection operations. During this time interval, the electrolyte can flow into the pores of the positive electrode sheet, the negative electrode sheet and the separator to infiltrate the electrode assembly, and create free space in the initial battery to facilitate the next injection after the rest treatment, reduce the injection resistance of the next injection, shorten the injection time of the next injection, and improve the injection efficiency of the next injection, thereby improving the injection efficiency of the overall injection, and further improving the production efficiency of the battery cell.

[0080] [Step S100]

[0081] The injection curve is constructed based on the injection time and injection amount of the battery sample obtained. Optionally, the injection curve is constructed based on the injection time and injection amount of the battery sample obtained during one injection process.

[0082] In the embodiment of the present application, a single injection refers to injecting 100% of the electrolyte into the battery sample over a continuous period of time. The injection curve constructed during a single injection process is more likely to reflect the inflection point that affects the injection efficiency. The injection curve can specifically be a curve with the injection time as the horizontal axis and the injection volume as the vertical axis; of course, the injection time can also be used as the vertical axis and the injection volume as the horizontal axis. Abnormal points can be eliminated in the process of constructing the injection curve. The detection device can collect multiple moments and the weight of the battery sample corresponding to each moment, so as to calculate the injection time and injection volume.

[0083] As shown in FIG. 2 , in some embodiments, step S100 may include:

[0084] Step S110, providing electrolyte to the battery sample;

[0085] The total injection volume required for the battery sample can be obtained based on the design parameters of the final product battery cell, or it can be detected and calculated using equipment and methods known in the art. For example, the electrolyte needs to fill the pores in the electrode assembly (positive electrode sheet, negative electrode sheet and separator), and there is free space between the shell and the electrode assembly (the free space can be calculated based on the design parameters of the final product battery cell), then the total injection volume of the electrolyte is equal to the sum of the pores and free space of the electrode assembly.

[0086] Step S120, obtaining the initial time of providing the electrolyte and the weight of the battery sample corresponding to the initial time, and obtaining the weights of the battery sample corresponding to multiple times, wherein the multiple times all occur after the initial time;

[0087] Steps S110 and S120 can occur simultaneously, i.e., during the process of providing the battery sample, the parameters of the battery sample are collected. Electrolyte injection into the battery sample begins at the initial time. It can be understood that at the initial time T0, the battery sample does not contain electrolyte, or the amount of electrolyte is 0. The weight of the battery sample obtained at this time is the weight M0 of the battery sample excluding electrolyte. The weight of the battery sample corresponding to multiple times during the process of injecting the electrolyte is obtained. The multiple times can be two, three, four, ten, one hundred, one thousand, and so on.

[0088] For example, take the example of multiple moments including three moments, moment T P Time T Q Time T S Occurs sequentially, i.e., time T P Occurs after the initial time T0, time T Q Occurs at time T P Afterwards, at time T S Occurs at time T Q after.

[0089] After the initial time, electrolyte is continuously injected into the battery sample. P Get the weight M of the battery sample P ;

[0090] Continue to inject electrolyte into the battery sample. At time T Q Get the weight M of the battery sample Q ;

[0091] Continue to inject electrolyte into the battery sample. At time T S Get the weight M of the battery sample S .

[0092] Step S130, calculating the difference between each moment and the initial moment as the injection time, and calculating the difference between the weight corresponding to each moment and the weight corresponding to the initial moment as the injection volume.

[0093] According to the above method of obtaining time and weight,

[0094] Calculation time T P The difference between the initial time T0 and the injection time T P -T0, the injection volume during this injection time is M P -M0.

[0095] Calculation time T Q The difference between the initial time T0 and the injection time T Q -T0, the injection volume during this injection time is M Q -M0.

[0096] Calculation time T S The difference between the initial time T0 and the injection time T S -T0, the injection volume during this injection time is M S -M0.

[0097] Step S140: constructing an injection curve based on the injection time and injection volume.

[0098] The injection time and the injection volume corresponding to the injection time are taken as coordinate points, and the coordinate points include (T P -T0,M P -M0)、(T Q -T0,M Q -M0)、(T S -T0,M S -M0) etc. to construct an injection curve; for example, the injection curve is drawn in an XY plane rectangular coordinate system with the injection time as the horizontal axis and the injection time as the vertical axis. During the drawing of the injection curve, abnormal points can be removed to make the injection curve smooth, thereby more accurately reflecting the injection status.

[0099] Therefore, the embodiments of the present application can accurately obtain relevant injection parameters of the battery sample through the above steps, thereby improving the accuracy of injection curve construction.

[0100] [Step S200]

[0101] The injection curve is divided into at least two segments so that the average slopes of two adjacent injection curves are different, and the connection point of the two adjacent injection curves is used as the target time inflection point.

[0102] In the early stage of liquid filling, the free space in the battery sample is relatively sufficient, and the liquid filling resistance is relatively small. As the liquid filling time increases, the liquid filling amount increases significantly. In the liquid filling curve plotted with the liquid filling time as the horizontal axis and the liquid filling time as the vertical axis, the liquid filling curve has a large slope. In the later stage of liquid filling, the free space in the battery sample is less or even almost non-existent, and the liquid filling resistance is relatively large. As the liquid filling time increases, the liquid filling amount increases slowly. In the liquid filling curve plotted with the liquid filling time as the horizontal axis and the liquid filling time as the vertical axis, the liquid filling curve has a small slope.

[0103] Due to the above-mentioned injection characteristics, there is a large difference in the slope of the injection curve. The slope difference is used as the basis for curve division to confirm the target time inflection point. The target time inflection point can be at least one, such as one, two, three, etc. When there is one target time inflection point, the injection curve is divided into two sections. The average slope of each section of the injection curve can be understood as taking multiple coordinate points in the section to calculate the slope separately, and then taking the average value. The number of coordinate points can be five, ten, one hundred, etc. When there are two target time inflection points, the injection times corresponding to the two target time inflection points are different, that is, the horizontal coordinates are different. In this case, the injection curve is divided into three sections. When there are three target time inflection points, the injection times corresponding to the three target time inflection points are different, that is, the horizontal coordinates are different. In this case, the injection curve is divided into four sections.

[0104] As the number of injection curve divisions increases, static treatment is performed between two adjacent injection operations. The static treatment increases the free space, so that the injection efficiency can be improved during the injection operation after the static treatment. However, static treatment is required during both adjacent injection operations, resulting in a large number of static treatments, which may result in little improvement in the injection efficiency during the overall injection process.

[0105] In order to further improve the injection efficiency, the embodiment of the present application further defines the slope difference. For example, in two adjacent injection curves, the average slope of one injection curve is A, and the average slope of the other injection curve is B. The one with the larger average slope is defined as B, and the one with the smaller average slope is defined as A. -6 ≤A / B<1; alternatively, 1×10 -6 ≤A / B≤1×10 -1 For example, in an injection curve plotted with injection time as the horizontal axis and injection time as the vertical axis, the average slope in the early stage of injection is larger, and B can be the average slope in the early stage of injection; the average slope in the later stage of injection is smaller, and A can be the average slope in the later stage of injection. By defining the above formula, the injection operation can be performed more accurately in batches, thereby improving the injection efficiency of each single injection.

[0106] [Step S300]

[0107] The injection parameters are calculated according to the target time inflection point. The injection parameters include the number of injection operations and the injection volume corresponding to each injection operation.

[0108] The coordinate values ​​(injection time, injection volume corresponding to the injection time) and number of the target time inflection points correspond to the specific injection operation. When there is one target time inflection point, the injection curve is divided into two segments, and the injection operations are performed twice. The injection volume corresponding to each injection operation is calculated based on the injection volume coordinate value corresponding to each target time inflection point. When there are two target time inflection points, the injection curve is divided into three segments, and the injection operations are performed three times. The injection volume corresponding to each injection operation is calculated based on the injection volume coordinate value corresponding to each target time inflection point. When there are three target time inflection points, the injection curve is divided into four segments, and the injection operations are performed four times. The injection volume corresponding to each injection operation is calculated based on the injection volume coordinate value corresponding to each target time inflection point. When there are four target time inflection points, the injection curve is divided into five segments, and the injection operations are performed five times. The injection volume corresponding to each injection operation is calculated based on the injection volume coordinate value corresponding to each target time inflection point. Of course, there can be more target time inflection points, and the specific injection operation is determined based on the target time inflection point.

[0109] [Step S400]

[0110] Electrolyte is supplied to the initial battery according to the injection parameters, and a static treatment is performed between two adjacent injection operations to obtain an injected battery cell. The initial battery is the battery cell to be produced that does not contain electrolyte.

[0111] As shown in FIG3 , in some embodiments, the number of target time inflection points is one, and step S400 may include:

[0112] Step S410, providing a first injection volume of electrolyte to an initial battery to obtain a pre-filled battery, wherein the number of injection operations in the injection parameters is two, and the injection volumes corresponding to the two injection operations are the first injection volume and the second injection volume, respectively;

[0113] Step S420, placing the pre-filled battery in a static state to obtain a static battery;

[0114] Step S430 , providing a second injection amount of electrolyte to the stationary battery to obtain a liquid-filled battery.

[0115] For example, there is one target time inflection point, and its corresponding horizontal coordinate is 20% of the total injection time (the total injection time refers to the time corresponding to the completion of all electrolyte injections of the battery sample during one injection process), and its corresponding vertical coordinate is 70% of the total injection volume (the total injection volume is the required injection volume calculated based on the design parameters of the battery sample). According to the above target time inflection point, the injection curve is divided into two curves, and the injection operation is also divided into two times. The first injection is to inject 70% of the total injection volume (i.e., the first injection volume) into the initial battery to obtain a pre-injected battery. After the first injection, a static treatment is performed, and after the static treatment, a second injection is performed. The second injection is to inject 30% of the total injection volume (i.e., the second injection volume) into the battery sample to complete the injection operation. According to the above operation, the injection efficiency of the second injection process can be significantly improved, so that the efficiency of a single injection is higher, thereby improving the injection efficiency of the overall injection process.

[0116] As shown in FIG4 , in some embodiments, the number of target time inflection points is two, and step S400 may include:

[0117] Step S440, providing a first injection volume of electrolyte to the initial battery to obtain a pre-filled battery, wherein the number of injection operations in the injection parameters is three, and the injection volumes corresponding to the three injection operations are the first injection volume, the second injection volume, and the third injection volume, respectively;

[0118] Step S450, placing the pre-filled battery in a static state to obtain a pre-static battery;

[0119] Step S460: Provide the second injection amount of electrolyte to the pre-static battery to obtain a refill battery;

[0120] Step S470, placing the refilled battery in a static state to obtain a rested battery;

[0121] Step S480: Provide a third injection amount of electrolyte to the resting battery to obtain a liquid-injected battery.

[0122] For example, there are two target time inflection points. The first target time inflection point corresponds to a horizontal coordinate of 20% of the total injection time and a vertical coordinate of 70% of the total injection volume. The second target time inflection point corresponds to a horizontal coordinate of 40% of the total injection time and a vertical coordinate of 85% of the total injection volume. Based on the above target time inflection points, the injection curve is divided into three curves, and the injection operation is also divided into three times. The first injection is to inject 70% of the total injection volume (i.e., the first injection volume) into the battery sample. After the first injection, a static treatment is performed. After the static treatment, the second injection is performed. The second injection is to inject 15% (i.e., 85% minus 70%) of the total injection volume (i.e., the second injection volume) into the battery sample. After the second injection, a static treatment is performed. After the static treatment, the third injection is performed. The third injection is to inject 15% of the total injection volume (i.e., the third injection volume) into the battery sample to complete the injection operation. Therefore, the embodiment of the present application can significantly improve the injection efficiency of the second injection process and the third injection process through the above operations, so that the efficiency of a single injection is higher, thereby improving the injection efficiency of the entire injection process.

[0123] Of course, there can be three target time inflection points, and corresponding to these target time inflection points, four injection operations are performed, and the injection volume corresponding to each injection operation is calculated based on the injection volume corresponding to each target time inflection point. Of course, the number of target time inflection points can be greater, and the parameters corresponding to the injection operations are calculated corresponding to these target time inflection points.

[0124] In some embodiments, the standing treatment time can be 0.1h to 10h. When the standing treatment time is within the above range, the electrolyte can infiltrate the interior of the electrode assembly, diffuse into the pores of the electrode assembly, and release free space, which is conducive to improving the injection efficiency after the standing treatment. Exemplarily, the standing treatment time can be 0.1h, 0.5h, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, or a range consisting of any two of the above values.

[0125] In some embodiments, the temperature of the static treatment is 20°C to 65°C. When the temperature of the static treatment is within the above range, the electrolyte can infiltrate the interior of the electrode assembly, diffuse into the pores of the electrode assembly, and release free space, which is conducive to improving the injection efficiency after the static treatment. Exemplarily, the temperature of the static treatment can be 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, or a range consisting of any two of the above values.

[0126] In some embodiments, a further vacuum treatment can be performed after the resting treatment, and the next injection operation can be performed after the vacuum treatment, which is more conducive to reducing injection resistance and improving injection efficiency. The air pressure inside the initial battery after the vacuum treatment can be 100 Pa to 30,000 Pa. Specifically, the electrolyte is provided to the initial battery according to the injection parameters, and the resting treatment and vacuum treatment are sequentially performed between two adjacent injection operations to obtain a liquid-injected battery.

[0127] As shown in FIG5 , in some embodiments, before step S400, step S500 is further included.

[0128] The initial battery is vacuum-treated so that the air pressure inside the initial battery meets a preset air pressure value.

[0129] Before liquid injection, the initial battery is vacuumed to achieve a certain degree of vacuum inside the initial battery, which is conducive to the liquid injection operation. Optionally, the preset air pressure value is an absolute pressure value, which can be 100 Pa to 30,000 Pa, for example, 100 Pa, 200 Pa, 300 Pa, 500 Pa, 600 Pa, 700 Pa, 800 Pa, 1000 Pa, 1200 Pa, 1300 Pa, 1500 Pa, 1800 Pa, 1900 Pa, 2000 Pa, 3000 Pa, 4000 Pa, 5000 Pa, 8000 Pa, 10000 Pa, 12000 Pa, 15000 Pa, 18000 Pa, 20000 Pa, 25000 Pa, 30000 Pa, or a range consisting of any two of the above values.

[0130] The above-mentioned liquid injection method described in the embodiment of the present application can be used to prepare battery cells.

[0131] In some embodiments, a method for preparing a battery cell includes:

[0132] A liquid-filled battery is prepared according to the liquid-filled method provided in each of the above embodiments; and the liquid-filled battery is subjected to operations such as formation to prepare a battery cell.

[0133] The above-mentioned liquid injection method described in the embodiment of the present application is applicable to a liquid injection system and a battery cell manufacturing system.

[0134] FIG6 shows a schematic structural diagram of a battery cell manufacturing system 1 according to an embodiment of the present application.

[0135] As shown in FIG6 , a battery cell manufacturing system 1 is used to manufacture battery cells. The manufacturing system 1 may include a liquid injection system 10 configured to inject liquid into the battery cells.

[0136] In some embodiments, the manufacturing system 1 may further include a pole piece manufacturing device, which is used to manufacture positive pole pieces, negative pole pieces, etc.

[0137] In some embodiments, the manufacturing system 1 may further include an electrode assembly manufacturing device, which is used to wind or stack the positive electrode sheets, separators, and negative electrode sheets into an electrode assembly.

[0138] In some embodiments, the manufacturing system 1 may further include a shell insertion device, which is used to assemble the electrode assembly into the shell.

[0139] In some embodiments, the manufacturing system 1 may further include a sealing device, which is used to seal the shell.

[0140] In some embodiments, the manufacturing system 1 may further include a formation device, which is used to perform a formation operation on the battery cells to activate active materials in the electrode assembly.

[0141] Of course, the manufacturing system 1 may also include, in addition to the devices listed above, other devices that are well known in the art and are essential for manufacturing battery cells, which will not be described in detail here.

[0142] FIG7 shows a schematic structural diagram of a liquid injection system 10 according to an embodiment of the present application.

[0143] As shown in Figure 7, the injection system 10 includes a detection device 100, a control device 200 and an electrolyte providing device 300. The detection device 100 is configured to detect the time and the weight of the battery sample corresponding to the time. The control device 200 is configured to calculate the injection parameters based on the time detected by the detection device 100 and the weight of the battery sample; the electrolyte providing device 300 is configured to provide electrolyte to the initial battery according to the injection parameters.

[0144] The electrolyte providing device 300 can be understood as a device for injecting electrolyte into a battery sample, and specifically, equipment known in the art can be used.

[0145] The control device 200 calculates the injection parameters suitable for the initial battery through the data pre-detected by the detection device 100, and injects the initial battery, which can effectively improve the injection efficiency.

[0146] FIG8 shows a schematic structural diagram of a control device 200 according to an embodiment of the present application.

[0147] As shown in FIG8 , the control device 200 may include a processor 201 . The processor 201 may include a central processing unit (CPU) or an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0148] The control device 200 may also include a memory 202 storing computer program instructions, and the memory 202 may include a large-capacity memory 202 for data or instructions. By way of example and not limitation, the memory 202 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive, or a combination of two or more of these. Where appropriate, the memory 202 may include removable or non-removable (or fixed) media. Where appropriate, the memory 202 may be inside or outside the integrated gateway disaster recovery device. In a specific embodiment, the memory 202 is a non-volatile solid-state memory.

[0149] In certain embodiments, the memory 202 may include read-only memory (ROM), random access memory (RAM), magnetic disk storage media devices, optical storage media devices, flash memory devices, electrical, optical, or other physical / tangible memory 202 storage devices. Thus, generally, the memory 202 includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors 201), it is operable to perform the operations described with reference to the method according to an aspect of the present application.

[0150] The processor 201 reads and executes computer program instructions stored in the memory 202 to implement any one of the injection methods in the above embodiments.

[0151] In one example, the control device 200 may further include a communication interface 203 and a communication bus 204. As shown in FIG8 , the processor 201, the memory 202, and the communication interface 203 are connected via the communication bus 204 and communicate with each other.

[0152] The communication interface 203 is mainly used to implement communication between various modules, devices, units and / or equipment in the embodiments of the present application.

[0153] The communication bus 204 includes hardware, software or both, coupling the components of the image processing device to each other. For example, and not limitation, the bus may include an accelerated graphics port (AGP) or other graphics bus, an enhanced industry standard architecture (EISA) bus, a front-side bus (FSB), a hypertransport (HT) interconnect, an industry standard architecture (ISA) bus, an infinite bandwidth interconnect, a low pin count (LPC) bus, a memory bus, a microchannel architecture (MCA) bus, a peripheral component interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a serial advanced technology attachment (SATA) bus, a video electronics standard association local (VLB) bus or other suitable bus or a combination of two or more of these. Where appropriate, the communication bus 204 may include one or more buses. Although the present application describes and illustrates a specific bus, the present application contemplates any suitable bus or interconnect.

[0154] The liquid injection device can execute the liquid injection method in the embodiment of the present application, thereby realizing the liquid injection method described in combination with the above embodiment.

[0155] In addition, in conjunction with the liquid injection method in the above embodiment, the present application embodiment can provide a computer storage medium for implementation. The computer storage medium stores computer program instructions; when the computer program instructions are executed by a processor, any one of the liquid injection methods in the above embodiment is implemented.

[0156] In addition, an embodiment of the present application further provides a computer program product, including a computer program, which can implement the steps and corresponding contents of the aforementioned method embodiment when executed by a processor.

[0157] FIG9 shows a schematic structural diagram of a detection device 100 according to an embodiment of the present application.

[0158] As shown in Figure 9, in some embodiments, the detection device 100 includes a collection component 110, a containing component 120 and an injection component 130. The collection component 110 is configured to obtain the weight of the battery sample at multiple moments and each moment; the containing component 120 is arranged on the collection component 110, and the containing component 120 includes a containing cavity 121 having at least one opening 122, and the containing cavity 121 is configured to contain the battery sample; the injection component 130 is arranged opposite to the opening 122, and the injection component 130 is configured to be connected to or disconnected from the battery sample.

[0159] The detection device 100 uses the battery sample as a test sample to detect the injection-related parameters of the battery sample, transmits the detected relevant parameters to the control device 200, and designs a more preferred injection operation to inject the initial battery.

[0160] The collection component 110 can be used to collect the time and weight of the battery sample. The collection component 110 can include equipment such as an electronic scale, which can record the weight data of the battery sample changing over time in real time.

[0161] The containment assembly 120 is used to hold the battery sample, thereby supporting and securing the battery sample and improving the accuracy of data acquired by the acquisition assembly 110. The containment assembly 120 may include a containment cavity 121 with at least one opening 122. The battery sample is positioned within the containment cavity 121. The opening 122 is positioned opposite the liquid injection assembly 130 to facilitate liquid injection by the liquid injection assembly 130. The number of openings 122 may be one, two, or even one. The containment assembly 120 can be designed based on the housing structure of the battery sample. For example, if the battery sample housing is cylindrical, the containment cavity 121 of the containment assembly 120 can be cylindrical. Alternatively, if the battery sample housing is square, the containment cavity 121 of the containment assembly 120 can be rectangular. For example, the containment cavity 121 can be enclosed by multiple connectors. In some embodiments, the gap between the containment cavity 121 and the battery cell can be 0 to 1 mm, thereby constraining the battery cell and reducing the risk of volume expansion.

[0162] The liquid injection assembly 130 is disposed opposite the opening 122 and is used to communicate with the interior of the battery sample to provide electrolyte into the battery sample and detect injection-related parameters of the battery sample. After the injection is completed, the liquid injection assembly 130 can be disconnected from the battery sample. In some embodiments, the liquid injection assembly 130 includes a liquid injection piece 131 and a pneumatic line 132. The liquid injection piece 131 includes a liquid injection line 1311 and a liquid injection portion 1322 connected to the liquid injection line 1311. The liquid injection line 1311 is configured to communicate with external electrolyte, and the liquid injection portion 1322 is configured to be connected to or disconnected from the battery sample. The pneumatic line 132 is disposed in the liquid injection portion 1322. The pneumatic line 132 is configured to communicate with an external air circuit and is configured to be connected to or disconnected from the battery sample through the liquid injection portion 1322. Before injecting liquid into the battery sample, the pneumatic line 132 can be connected to the interior of the battery sample to extract the gas inside the battery sample, creating a certain vacuum inside the battery sample, which is beneficial for subsequent liquid injection operations. After the gas extraction is completed, the pneumatic line 132 is disconnected from the battery sample. The injection line 1311 of the injection member 131 can be connected to the external electrolyte, so that the external electrolyte is stored in the injection part 1322. When the battery sample needs to be injected, the injection part 1322 is connected to the interior of the battery sample to inject the liquid. After the injection is completed, the injection part 1322 is disconnected from the battery sample. Optionally, the injection part 1322 can include an injection cup and an injection nozzle connected to the injection cup. The injection cup is used to store electrolyte, and the injection nozzle is used to connect and disconnect with the battery sample. The injection cup can be used to connect to the electrolyte pipeline and can be connected to the pneumatic line 132.

[0163] Therefore, the detection device 100 according to the embodiment of the present application can accurately obtain relevant injection parameters of the battery sample and improve the accuracy of the injection curve construction.

[0164] As shown in FIG9 , in some embodiments, the detection device 100 of the present application can further include a bracket assembly 140. The bracket assembly 140 can cooperate with the liquid injection assembly 130 to adjust the distance between the liquid injection assembly 130 and the battery cell to facilitate liquid injection and vacuuming operations. Specifically, the bracket assembly 140 includes a base 141 and a guide member 142. The collection assembly 110 is disposed on the base 141. The guide member 142 includes a support portion 1421 and a sliding portion 1422. The support portion 1421 is connected to the base 141. The sliding portion 1422 is fixedly connected to the liquid injection assembly 130. The sliding portion 1422 is connected to the support portion 1421. The sliding portion 1422 has a first state and a second state. In the first state, the sliding portion 1422 is movably connected to the support portion 1421 to drive the liquid injection assembly 130 to move toward or away from the receiving assembly 120. In the second state, the sliding portion 1422 is locked to the support portion 1421.

[0165] The base 141 plays a supporting role, and is used to support the collection component 110 and further support the receiving component 120 provided on the collection component 110 .

[0166] The support portion 1421 of the guide member 142 can be fixedly connected to the base 141, providing further support and guidance. The sliding portion 1422 is connected to the support portion 1421. When liquid injection or vacuuming is required, the sliding portion 1422 drives the liquid injection assembly 130 toward the opening 122 of the container assembly 120, thereby approaching the opening 122 of the container assembly 120. In this state, the sliding portion 1422 is movably connected to the support portion 1421, and the sliding portion 1422 is in a first state. After the liquid injection assembly 130 is moved into position, the sliding portion 1422 and the support portion 1421 are locked, and the sliding portion 1422 is in a second state, and the liquid injection assembly 130 begins to perform the liquid injection or vacuuming operation. After the liquid injection assembly 130 performs the liquid injection or vacuuming operation, the sliding portion 1422 drives the liquid injection assembly 130 to move away from the container assembly 120, thereby moving away from the opening 122 of the container assembly 120.

[0167] Optionally, the sliding portion 1422 and the supporting portion 1421 can move along the extension direction of the supporting portion 1421, and the extension direction of the supporting portion 1421 is parallel to the first direction X. For example, the receiving assembly 120 and the liquid injection assembly 130 are arranged relative to each other along the first direction X. In the first state of the sliding portion 1422, the sliding portion 1422 and the supporting portion 1421 are movably connected along the first direction X to drive the liquid injection assembly 130 to move toward or away from the receiving assembly 120 along the first direction X. In this case, the supporting portion 1421 can serve as a guide, improving the movement accuracy of the liquid injection assembly 130.

[0168] Further optionally, the collection component 110 , the containing component 120 and the liquid injection component 130 may be sequentially arranged along the first direction X. This arrangement is conducive to collecting parameters of the battery sample and facilitates the precise movement of the liquid injection component 130 .

[0169] Further optionally, the base 141 , the collection assembly 110 , the receiving assembly 120 and the injection assembly 130 may be sequentially arranged along the first direction X. This arrangement is conducive to collecting parameters of battery samples and facilitating precise movement of the injection assembly 130 .

[0170] As shown in Figure 10, as a specific embodiment of the present application for testing the injection-related parameters of the battery sample 2, the detection device 100 includes a collection component 110, a containing component 120, an injection component 130 and a bracket component 140. The collection component 110 is configured to obtain the weight of the battery sample 2 at multiple moments and corresponding to each moment; the containing component 120 is arranged on the collection component 110, and the containing component 120 includes a containing cavity 121 having at least one opening 122, and the containing cavity 121 is configured to contain the battery sample 2; the injection component 130 is arranged opposite to the opening 122, and the injection component 130 is configured to be connected to or disconnected from the battery sample 2. The bracket assembly 140 includes a base 141 and a guide member 142, and the collection assembly 110 is arranged on the base 141; the guide member 142 includes a supporting portion 1421 and a sliding portion 1422, the supporting portion 1421 is connected to the base 141, the sliding portion 1422 is fixedly connected to the injection assembly 130, and the sliding portion 1422 is connected to the supporting portion 1421. The sliding portion 1422 includes a first state and a second state. In the first state, the sliding portion 1422 is movably connected to the support portion 1421 to drive the injection assembly 130 to move toward or away from the containing assembly 120; in the second state, the sliding portion 1422 is locked with the support portion 1421. The accommodating component 120 and the liquid injection component 130 are arranged relative to each other along the extension direction of the support portion 1421, that is, the first direction X. In the first state of the sliding portion 1422, the sliding portion 1422 is movably connected to the support portion 1421 along the first direction X to drive the liquid injection component 130 to move along the first direction X toward or away from the accommodating component 120.

[0171] Although illustrative embodiments have been shown and described, those skilled in the art should understand that the above embodiments should not be construed as limitations on the present application, and that changes, substitutions, and modifications may be made to the embodiments without departing from the spirit, principles, and scope of the present application.

Claims

1. A liquid injection method, characterized in that, Comprising: Construct a liquid injection curve based on the liquid injection time and liquid injection volume of the obtained battery sample; Divide the liquid injection curve into at least two segments so that the average slopes of adjacent two segments of the liquid injection curve are different, and take the connection point of adjacent two segments of the liquid injection curve as the target time inflection point; Calculate the liquid injection parameters according to the target time inflection point, where the liquid injection parameters include the number of liquid injection operations and the liquid injection volume corresponding to each liquid injection operation; Provide electrolyte to the initial battery according to the liquid injection parameters, and perform a standing treatment between adjacent two liquid injection operations to obtain a liquid-injected battery.

2. The liquid injection method according to claim 1, characterized in that, The step of providing electrolyte to the initial battery according to the liquid injection parameters and performing a standing treatment between adjacent two liquid injection operations to obtain a liquid-injected battery includes: Provide electrolyte with a first liquid injection volume to the initial battery to obtain a pre-liquid-injected battery, where the number of liquid injection operations in the liquid injection parameters is two, and the liquid injection volumes corresponding to the two liquid injection operations are the first liquid injection volume and the second liquid injection volume respectively; Perform a standing treatment on the pre-liquid-injected battery to obtain a standing battery; Provide the electrolyte with the second liquid injection volume to the standing battery to obtain a liquid-injected battery.

3. The liquid injection method according to claim 1, characterized in that, The step of providing electrolyte to the initial battery according to the liquid injection parameters and performing a standing treatment between adjacent two liquid injection operations to obtain a liquid-injected battery includes: Provide electrolyte with a first liquid injection volume to the initial battery to obtain a pre-liquid-injected battery, where the number of liquid injection operations in the liquid injection parameters is three, and the liquid injection volumes corresponding to the three liquid injection operations are the first liquid injection volume, the second liquid injection volume and the third liquid injection volume respectively; Perform a standing treatment on the pre-liquid-injected battery to obtain a pre-standing battery; Provide the electrolyte with the second liquid injection volume to the pre-standing battery to obtain a re-liquid-injected battery; Perform a standing treatment on the re-liquid-injected battery to obtain a re-standing battery; Provide the electrolyte with the third liquid injection volume to the re-standing battery to obtain a liquid-injected battery.

4. The liquid injection method according to any one of claims 1 to 3, characterized in that The time of the standing treatment is 0.1 h to 10 h; and / or the temperature of the standing treatment is 20°C to 65°C.

5. The liquid injection method according to any one of claims 1 to 4, characterized in that, Before the step of providing electrolyte to the initial battery according to the liquid injection parameters and performing a standing treatment between adjacent two liquid injection operations to obtain a liquid-injected battery, it further includes: Perform a vacuum treatment on the initial battery so that the air pressure inside the initial battery meets a preset air pressure value.

6. The liquid injection method according to any one of claims 1 to 5, characterized in that, The preset air pressure value is 100 Pa to 30000 Pa.

7. The liquid injection method according to any one of claims 1 to 6, characterized in that, The step of constructing a liquid injection curve based on the liquid injection time and liquid injection volume of the battery sample includes: Provide the electrolyte to the battery sample; Obtain the initial moment when providing the electrolyte and the weight of the battery sample corresponding to the initial moment, and obtain the weights of the battery sample corresponding to multiple moments respectively, where multiple of the moments all occur after the initial moment; Calculate the difference between each moment and the initial moment as the liquid injection time, and calculate the difference between the weight corresponding to each moment and the weight corresponding to the initial moment as the liquid injection volume; Construct a liquid injection curve based on the liquid injection time and the liquid injection volume. ​ 8. The liquid injection method according to any one of claims 1 to 7, characterized in that The average slope of one of the two adjacent liquid injection curves is A, and the average slope of the other liquid injection curve is B, where 1×10 -6 ≤A / B<1; Optionally, 1×10 -6 ≤A / B≤1×10 -1 .

9. A detection device, characterized in that a collection component configured to obtain the weights of a battery specimen at multiple moments and corresponding to each of the moments; a housing component disposed on the collection component, the housing component including a housing cavity having at least one opening, the housing cavity being configured to house a battery specimen; and a liquid injection component disposed opposite to the opening, the liquid injection component being configured to communicate with or disconnect from the battery specimen.

10. The detection device according to claim 9, characterized in that, The detection device further includes a bracket component, and the bracket component includes: a base, on which the collection component is disposed; and a guide member including a support portion and a sliding portion, the support portion being connected to the base, the sliding portion being fixedly connected to the liquid injection component, the sliding portion being connected to the support portion, the sliding portion including a first state and a second state. In the first state, the sliding portion is movably connected to the support portion to drive the liquid injection component to move in a direction towards or away from the housing component; in the second state, the sliding portion is locked to the support portion.

11. The detection device according to claim 10, wherein The support portion extends in a first direction; the housing component and the liquid injection component are disposed opposite to each other in the first direction. In the first state, the sliding portion is movably connected to the support portion to drive the liquid injection component to move in the first direction towards or away from the housing component.

12. The detection device according to any one of claims 9 to 11, characterized in that, The liquid injection component includes: a liquid injection member including a liquid injection pipeline and a liquid injection portion communicating with the liquid injection pipeline, the liquid injection pipeline being configured to communicate with an external electrolyte, the liquid injection portion being configured to communicate with or disconnect from the battery specimen; and a pneumatic pipeline disposed on the liquid injection portion, the pneumatic pipeline being configured to communicate with an external gas path, and the pneumatic pipeline being configured to communicate with or disconnect from the battery specimen through the liquid injection portion.

13. A liquid injection system, characterized in that, including: the detection device according to any one of claims 9 to 12; a control device configured to calculate liquid injection parameters according to the moments detected by the detection device and the weight of the battery specimen; an electrolyte supply device configured to supply electrolyte to an initial battery according to the liquid injection parameters.

14. A manufacturing system for a battery cell, characterized in that, including the liquid injection system according to claim 13.

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