Method and apparatus for manufacturing battery, and control system

Abstract

Provided in the embodiments of the present application are a method and apparatus for manufacturing a battery, and a control system. The method comprises: performing formation treatment on a battery cell; performing a self-discharge rate (K-value) test and / or an aging test on the battery cell which has undergone the formation treatment, such that the voltage of the battery cell is stable; performing a direct-current resistance test and a capacity test on the battery cell which has undergone the self-discharge rate (K-value) test and / or the aging test; performing a capacity test on the battery cell which has undergone the direct-current resistance test; and performing grading on the battery cell on the basis of a result of the direct-current resistance test and / or a result of the capacity test. The method and apparatus, and the control system in the embodiments of the present application can prolong the service life of a product.

Description

Method, device and control system for manufacturing battery Technical Field

[0001] The embodiments of the present application relate to the field of battery technology, and in particular to a method, device, and control system for manufacturing a battery. Background Art

[0002] Due to the high voltage and large capacity requirements of existing energy storage systems, a large number of batteries are assembled in series and parallel into containers, which then exchange energy with the power grid through energy storage inverters. During the container assembly process, the poor consistency between the parallel battery groups leads to uneven current flow between container clusters, which affects the power utilization of the entire system container and reduces its overall lifespan.

[0003] Summary of the Invention

[0004] In view of this, embodiments of the present application provide a method, device, and control system for manufacturing a battery, which can increase the life of the product.

[0005] In a first aspect, a method for manufacturing a battery is provided, comprising: performing a formation treatment on a battery cell; performing a self-discharge rate K value test and / or an aging test on the battery cell that has undergone the formation treatment to stabilize the voltage of the battery cell; performing a DC resistance test on the battery cell that has undergone the self-discharge rate K value test and / or the aging test; performing a capacity test on the battery cell after the DC resistance test; and grading the battery cells based on the results of the DC resistance test and / or the results of the capacity test.

[0006] By performing DC resistance and capacity tests on battery cells after conducting self-discharge rate K value and / or aging tests, more accurate DC resistance and capacity data can be obtained. By grading battery cells based on the results of DC resistance and capacity tests, the problem of poor consistency between parallel batteries can be effectively solved, thereby improving the life of battery products.

[0007] In one possible implementation, the battery cell is subjected to a formation treatment, including: forming the battery cell to a first state of charge value; and performing a DC resistance test and a capacity test on the battery cell that has passed the self-discharge rate K value test and / or the aging test, including: performing a DC resistance test on the battery cell that has passed the self-discharge rate K value test and / or the aging test at the first state of charge value.

[0008] Directly performing a DC resistance test on the battery cell at the first state of charge value after formation can simplify the process of the DC resistance test.

[0009] In one possible implementation, the method further includes: converting a first DC resistance value obtained by performing a DC resistance test at a first state of charge value into a second DC resistance value at a second state of charge value; wherein the second state of charge value is located in the state of charge range at the charging end, or the second state of charge value is located in the state of charge range at the discharging end.

[0010] Because uneven current flow between batteries typically occurs at the end of charging or discharging, converting the first DC resistance value at the first state of charge to a second DC resistance value at the second state of charge at the end of charging or discharging can minimize the impact of DC resistance differences between battery cells on uneven current flow. Furthermore, compared to directly adjusting the battery cell's state of charge to the second state of charge before performing a DC resistance test, this reduces test time and speeds up mass production.

[0011] In one possible implementation, a DC resistance test and a capacity test are performed on a battery cell that has undergone a self-discharge rate K value test and / or an aging test, including: adjusting the state of charge of the battery cell that has undergone the self-discharge rate K value test and / or the aging test to a second state of charge value; and performing a DC resistance test on the battery cell at the second state of charge value; wherein the second state of charge value is located in the state of charge range at the charging end, or the second state of charge is located in the state of charge range at the discharging end.

[0012] By directly performing a DC resistance test on the battery cell at the second state of charge value at the charging end or the discharging end, the accuracy of obtaining the second DC resistance value can be improved.

[0013] In a possible implementation, performing a DC resistance test on the battery cell at the second state of charge value includes: performing a DC resistance test on the battery cell at the second state of charge value when the battery cell is left stationary for a preset time period.

[0014] After the state of charge of the battery cell is adjusted to the second state of charge value at the charging end or the discharging end, the battery cell is subjected to a DC resistance test after sufficient rest, so that the voltage of the battery cell tends to be stable before the test, thereby further improving the accuracy of the second DC internal resistance value.

[0015] In a possible implementation, the state of charge interval at the charging end is [75%, 100%], and / or the state of charge interval at the discharging end is [10%, 25%].

[0016] In one possible implementation, the battery cell includes multiple battery cells, and a DC resistance test is performed on the multiple battery cells that have undergone the self-discharge rate K value test and / or the aging test, including: performing a DC resistance test on the multiple battery cells that have undergone the self-discharge rate K value test and / or the aging test to obtain a first DC resistance value of each battery cell in the multiple battery cells; based on the results of the DC resistance test and / or the results of the capacity test, the multiple battery cells are graded, including: performing time correction and / or temperature correction on the first DC resistance value of each battery cell respectively to obtain a third DC resistance value of each battery cell; and based on the third DC resistance values ​​of the multiple battery cells, the multiple battery cells are graded.

[0017] The first DCR value of the battery cell obtained through the DC resistance test is time-corrected and / or temperature-corrected to obtain a second DCR value of the battery cell, which is used as the basis for DCR grading, making the DCR control of the battery more accurate.

[0018] In one possible implementation, multiple battery cells are graded based on the third DC resistance values ​​of the multiple battery cells, including: when the sum of the third DC resistance values ​​of N battery cells among the multiple battery cells is within a first preset range, N battery cells are assembled into a battery pack, where N is a positive integer greater than 1.

[0019] When assembling a battery pack, a DCR control range is given for the battery pack, and only when the sum of the second DCR values ​​of the N battery cells is monitored to be within the DCR control range are the N battery cells assembled into a battery pack. This method has simple control steps and is easy to operate. It is also beneficial to improving the consistency of DCR between battery packs, reducing the probability of uneven current during the charging or discharging process, and ultimately extending the life of the product.

[0020] In one possible implementation, multiple battery cells are graded based on the third DC resistance values ​​of the multiple battery cells, including: when the third DC resistance value of each battery cell in N battery cells among the multiple battery cells is within a second preset range, N battery cells are assembled into a battery pack, where N is a positive integer greater than 1.

[0021] Each battery cell is graded according to its second DCR value, and finally N battery cells belonging to the same grade are assembled into a battery pack. This method has simple control steps and is easy to operate. It can also improve the consistency of DCR between battery cells in the battery pack.

[0022] In a possible implementation, the method further includes: determining a DC resistance value of the battery pack according to a third DC resistance value of each battery cell in the N battery cells.

[0023] The DCR value of the battery pack can be calculated based on the second DCR value of each battery cell in the multiple battery cells. This eliminates the need for DCR testing of the battery pack, saving production line equipment costs and improving production capacity. Furthermore, obtaining the DCR value of each battery cell helps understand the balance within the battery pack, thereby improving the performance of the entire battery pack.

[0024] In one possible implementation, the battery pack also includes a connecting component, which determines the DC resistance value of the battery pack based on the third DC resistance values ​​of the N battery cells, including: determining the sum of the third DC resistance values ​​of the N battery cells and the sum of the resistance value of the connecting component as the DC resistance value of the battery pack.

[0025] By determining the DCR value of the battery pack as the sum of the second DCR values ​​of N battery cells and the sum of the resistance values ​​of the connecting components, on the one hand, the resistance of the connecting components is taken into account. Compared with directly using the sum of the second DCR values ​​of N battery cells as the DC internal resistance value of the battery pack, the accuracy of the DC internal resistance of the battery pack is improved; on the other hand, compared with obtaining the DC internal resistance of the battery pack through testing, it can save production line equipment costs and improve production capacity.

[0026] In a possible implementation, the battery unit is a battery cell, and the battery pack is an electrical box; or, the battery unit is an electrical box, and the battery pack is an electrical cabinet.

[0027] In a possible implementation, the method further includes: storing the correspondence between the first DC resistance values ​​of the plurality of battery cells and their respective identifiers in at least one of a manufacturing execution system, a battery management system, a cloud server, and a local database.

[0028] In a second aspect, a device for manufacturing a battery is provided, comprising: a formation unit for performing formation treatment on a battery cell; a K value test and / or aging test unit for performing a self-discharge rate K value test and / or an aging test on the battery cell that has undergone the formation treatment, so as to stabilize the voltage of the battery cell; a DC resistance test and capacity test unit for performing a DC resistance test and a capacity test on the battery cell that has undergone the self-discharge rate K value test and / or the aging test; and a grading unit for grading the battery cell based on the results of the DC resistance test and / or the results of the capacity test.

[0029] In one possible implementation, the formation unit is specifically used to: form the battery cell to a first state of charge value; the DC resistance test and capacity test unit is specifically used to: perform a DC resistance test on the battery cell that has undergone the self-discharge rate K value test and / or aging test at the first state of charge value.

[0030] In one possible implementation, the device also includes: a conversion unit for converting a first DC resistance value obtained by performing a DC resistance test at a first state of charge value into a second DC resistance value at a second state of charge value; wherein the second state of charge value is located in the state of charge range at the charging end, or the second state of charge value is located in the state of charge range at the discharging end.

[0031] In one possible implementation, the DC resistance test and capacity test unit is specifically used to: adjust the state of charge of the battery cell that has undergone the self-discharge rate K value test and / or aging test to a second state of charge value; and perform a DC resistance test on the battery cell at the second state of charge value; wherein the second state of charge value is located in the state of charge range at the charging end, or the second state of charge is located in the state of charge range at the discharging end.

[0032] In a possible implementation, the DC resistance test and capacity test unit is specifically configured to perform a DC resistance test on the battery cell at a second state of charge value when the battery cell is left to rest for a preset period of time.

[0033] In a possible implementation, the state of charge interval at the charging end is [75%, 100%], and / or the state of charge interval at the discharging end is [10%, 25%].

[0034] In one possible implementation, the battery cell includes multiple battery cells, and the DC resistance test and capacity test unit is specifically used to: perform a DC resistance test on multiple battery cells that have undergone a self-discharge rate K value test and / or an aging test to obtain a first DC resistance value of each battery cell in the multiple battery cells; the grading unit is specifically used to: perform time correction and / or temperature correction on the first DC resistance value of each battery cell respectively to obtain a third DC resistance value of each battery cell; and grade the multiple battery cells based on the third DC resistance values ​​of the multiple battery cells.

[0035] In one possible implementation, the grading unit is specifically used to: assemble N battery cells among the multiple battery cells into a battery pack when the sum of the third DC resistance values ​​of N battery cells is within a first preset range, where N is a positive integer greater than 1.

[0036] In one possible implementation, the grading unit is specifically used to: assemble N battery cells into a battery pack when the third DC resistance value of each battery cell in N battery cells among the multiple battery cells is within a second preset range, where N is a positive integer greater than 1.

[0037] In a possible implementation, the device further includes: a determining unit, configured to determine a DC resistance value of the battery pack according to a third DC resistance value of each battery cell in the N battery cells.

[0038] In a possible implementation, the battery pack further includes a connecting component, and the determining unit is specifically configured to determine the DC resistance value of the battery pack by taking the sum of the third DC resistance values ​​of the N battery cells and the sum of the resistance value of the connecting component.

[0039] In a possible implementation, the battery unit is a battery cell, and the battery pack is an electrical box; or, the battery unit is an electrical box, and the battery pack is an electrical cabinet.

[0040] In one possible implementation, the device further includes: a storage unit for storing the correspondence between the first DC resistance values ​​of multiple battery cells and their respective identifiers in at least one of a manufacturing execution system, a battery management system, a cloud server, and a local database.

[0041] In a third aspect, a control system is provided, comprising a memory and a processor, wherein the memory is used to store instructions, and the processor is used to read the instructions and execute the method in the first aspect and any possible implementation of the first aspect according to the instructions.

[0042] In a fourth aspect, a chip is provided, comprising a processor for calling and running a computer program from a memory, so that a device equipped with the chip executes the method in the first aspect and any possible implementation of the first aspect.

[0043] In a fifth aspect, a computer program is provided, which enables a computer to execute the method in the first aspect and any possible implementation manner of the first aspect.

[0044] In a sixth aspect, a computer-readable storage medium is provided for storing a computer program, wherein the computer program enables a computer to execute the method in the first aspect and any possible implementation manner of the first aspect.

[0045] In a seventh aspect, a computer program product is provided, comprising computer program instructions, which enable a computer to execute the method in the first aspect and any possible implementation manner of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] 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.

[0047] FIG1 is a schematic diagram showing an application scenario of the battery grading method provided in an embodiment of the present application.

[0048] FIG2 is a schematic block diagram of a first method for manufacturing a battery according to an embodiment of the present application.

[0049] FIG3 is a schematic block diagram of a second method for manufacturing a battery according to an embodiment of the present application.

[0050] FIG4 is a schematic block diagram of a third method for manufacturing a battery according to an embodiment of the present application.

[0051] FIG5 is a schematic block diagram of a fourth method for manufacturing a battery according to an embodiment of the present application.

[0052] FIG6 shows a schematic curve diagram of DCR-storage time according to an embodiment of the present application.

[0053] FIG7 is a schematic block diagram of a fifth method for manufacturing a battery according to an embodiment of the present application.

[0054] FIG8 shows a production process diagram of an assembled electrical cabinet according to an embodiment of the present application.

[0055] FIG9 shows an assembly diagram of an electrical box according to an embodiment of the present application.

[0056] FIG10 shows another assembly diagram of the electrical box according to an embodiment of the present application.

[0057] FIG. 11 shows a schematic curve diagram of the resistance value and temperature of the connection component according to an embodiment of the present application.

[0058] FIG12 shows a schematic block diagram of an apparatus for manufacturing a battery according to an embodiment of the present application.

[0059] FIG13 shows another schematic block diagram of an apparatus for manufacturing a battery according to an embodiment of the present application.

[0060] FIG14 shows a schematic block diagram of a control system for manufacturing batteries according to an embodiment of the present application. DETAILED DESCRIPTION

[0061] The following detailed description of the embodiments of the present application is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present application, but are not intended to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0062] In the description of this application, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inside", "outside", etc., indicating directions or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly perpendicular, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0063] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of this application. In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0064] The term "and / or" in this application simply describes an association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0065] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0066] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0067] A battery refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, a battery can be a battery pack. A battery pack in this application refers to a battery assembly consisting of battery cells connected in series, parallel or in a hybrid manner, wherein hybrid refers to a mixture of series and parallel connections. For example, a battery pack in this application can be an electrical box, and a battery cell is a battery cell, that is, an electrical box can be formed by multiple battery cells connected in series and / or in parallel. For another example, a battery pack in this application can be an electrical cabinet, which can also be called a battery cluster, and a battery cell is an electrical box, that is, an electrical cabinet is formed by multiple electrical boxes connected in series and / or in parallel.

[0068] Optionally, the battery in the embodiment of the present application can be a lithium-ion battery, a lithium metal battery, a lead-acid battery, a nickel-cathode battery, a nickel-hydrogen battery, a lithium-sulfur battery, a lithium-air battery or a sodium-ion battery, etc., and the embodiment of the present application does not make specific limitations on this.

[0069] Currently, energy storage systems require a large number of batteries to be connected in series and parallel to form containerized products due to their high voltage and large capacity requirements. These batteries then exchange energy with the grid through PCS. During the container assembly process, poor consistency between the parallel battery packs leads to reduced charge and discharge capacity and a shortened overall lifespan.

[0070] In view of this, an embodiment of the present application provides a method for manufacturing a battery, by performing a DC resistance test and a capacity test on the battery cell after performing a self-discharge rate K value and / or aging test, so as to obtain relatively accurate DC resistance data and capacity data; and grading the battery cells based on the results of the DC resistance test and the capacity test can effectively solve the problem of poor consistency between parallel batteries, thereby improving the life of the battery product.

[0071] Figure 1 illustrates a scenario diagram of the battery grading method provided in an embodiment of the present application. As shown in Figure 1, a battery cell is the smallest unit. An electrical box is composed of L battery cells connected in series and / or in parallel, where L is a positive integer greater than 1. An electrical cabinet is composed of P electrical boxes connected in series and / or in parallel, where P is a positive integer greater than 1. A container is composed of Q electrical cabinets connected in parallel, where Q is a positive integer greater than 1.

[0072] That is to say, the battery unit of the embodiment of the present application can be as small as a battery cell or as large as an electrical box or even an electrical cabinet. That is, the battery grading method provided in the embodiment of the present application can be applied to the assembly process of any battery product in Figure 1.

[0073] It should be understood that the technical solutions in the embodiments of the present application can be applied not only to energy storage batteries, but also to power batteries.

[0074] Figure 2 shows a schematic block diagram of a method 100 for manufacturing a battery according to an embodiment of the present application. Optionally, the method 100 may be executed by a control system in an automated battery production and assembly process, for example, by a Manufacturing Execution System (MES). The method 100 may include some or all of the following:

[0075] S110, performing formation treatment on the battery cells.

[0076] S120, performing a self-discharge rate K value test and / or an aging test on the battery cell that has undergone the formation treatment to stabilize the voltage of the battery cell.

[0077] S130, performing a DC resistance test and a capacity test on the battery cell that has passed the self-discharge rate K value test and / or the aging test.

[0078] S140 , classifying the battery cells based on the result of the DC resistance test and / or the result of the capacity test.

[0079] First, Direct Current Resistance (DCR) refers to the resistance encountered by current flowing through the interior of the battery when it is working, including ohmic internal resistance and polarization internal resistance. The ohmic internal resistance is mainly determined by the total conductivity of the battery, while the polarization internal resistance is mainly determined by the solid-phase diffusion coefficient of lithium ions in the electrode active material. During the test, ensure that the battery is fully resting and the voltage is at a stable value. Connect the battery to the test instrument, and then inject a small current into the battery through the test instrument to charge or discharge the battery for a short time. Calculate the DCR of the battery based on the measured voltage drop and the applied current. Secondly, the grading in the embodiment of the present application refers to the grading of the DCR and / or capacity of the battery cells. The ultimate goal of the grading is to assemble a fixed number of battery cells with small DCR differences and / or small capacity differences into a battery pack.

[0080] Typically, after production or assembly, battery cells are first subjected to a formation treatment to form a passivation film, i.e., a solid electrolyte interphase (SEI) film, between the electrode material and the electrolyte at the solid phase interface. This SEI film prevents damage to the electrode material, thereby improving cycle performance and life. Specifically, the formation treatment of a battery cell may include some or all of the following steps: 1. Pre-charging, in which the battery cell is pre-charged with a small current to activate the electrolyte and positive and negative active materials inside the battery cell; 2. Fast charging, in which a large current fast charge is performed after the pre-charging to rapidly increase the charge inside the battery cell to reach the expected capacity. During the first charging process, the positive and negative active materials will chemically react with the electrolyte to form an SEI film, which gradually stabilizes the chemical reactions inside the battery cell.

[0081] After the battery cells are subjected to formation treatment, a self-discharge rate K value test and / or an aging test may be performed on the battery cells.

[0082] Specifically, the self-discharge rate K value can be understood as the voltage drop per unit time, usually expressed in mv / h. It is an indicator used to measure the self-discharge rate of the battery. Its size is related to whether there are abnormal particles inside the battery cell that cause micro-short circuit self-discharge, and it can be used to evaluate the performance and stability of the battery cell. By testing the self-discharge rate K value, the self-discharge rate of the battery cell can be within the set standard range, thereby ensuring that the battery cell can work normally and reliably. Optionally, the self-discharge rate K value can be carried out at room temperature or at high temperature. The self-discharge rate K value at different temperatures will be different, and you can choose to test at different temperatures as needed.

[0083] Aging testing involves cycling battery cells through charge and discharge cycles to accelerate the chemical reactions within the cells, maintaining a stable state. Aging testing can help identify early or late-stage battery failures, thereby improving cell quality and stability. Aging testing can generally be divided into two types: room-temperature aging and high-temperature aging.

[0084] Optionally, the self-discharge rate K value test can be performed after high-temperature aging. After high-temperature aging, the side reactions within the battery cells are complete, and the battery cells are relatively stable. After sufficient time at room temperature after high-temperature aging, the battery cell temperature and internal state are relatively stable. Measuring the voltage drop over a certain period of time under stable chemical conditions can reflect the extent of physical self-discharge. A large K value indicates that there are micro-short-circuit points such as abnormal particles inside the battery cell, causing voltage drop.

[0085] Since the battery cell will have a stable voltage after the self-discharge rate K value test and / or aging test, this provides a stable initial voltage for the DCR test and capacity test. Therefore, performing the DCR test and capacity test after the self-discharge rate K value test and / or aging test on the battery cell can not only obtain more accurate DCR data, but also reduce the test time, save production time, and improve production capacity.

[0086] Currently, due to the large capacity requirements of high-voltage boxes, energy storage systems inevitably require batteries to be connected in parallel. Due to battery consistency and aging issues, differences in DCR, capacity, temperature, and SOC between parallel batteries at different times inevitably lead to current differences between parallel batteries, which in turn leads to circulating current and uneven current, affecting the capacity and power of the energy storage system. This phenomenon becomes more obvious as the state of health (SOH) increases.

[0087] Therefore, after obtaining the results of the DCR test and the capacity test, multiple battery cells can be classified based on the results of the DCR test and / or the capacity test, which is conducive to assembling multiple battery cells with small DCR differences and / or small capacity differences into a battery pack, thereby reducing the impact of DCR differences and / or capacity differences on the life of the battery pack.

[0088] In some embodiments, the capacity test can be performed after the DCR test, so that the capacity test equipment can be used at the same time without the need for additional equipment, thus saving costs.

[0089] Optionally, as shown in Figure 3, S110, i.e., performing formation treatment on the battery cell, includes: S111, forming the battery cell to a first state of charge value; S130, i.e., performing a DC resistance test and a capacity test on the battery cell that has passed the self-discharge rate K value test and / or the aging test, includes: S131, performing a DC resistance test on the battery cell that has passed the self-discharge rate K value test and / or the aging test at the first state of charge value.

[0090] In other words, the DCR test is performed on the battery cell at the SOC to which the battery cell is charged. For example, if the battery cell is charged to 21% SOC, that is, the first SOC value is 21%, the DCR test can be performed on the battery cell directly at the 21% SOC. For another example, if the battery cell is charged to 50% SOC, that is, the first SOC value is 50%, the DCR test can be performed on the battery cell directly at the 50% SOC. For another example, if the battery cell is charged to 90%, that is, the first SOC value is 90%, the DCR test can be performed on the battery cell directly at the 90% SOC.

[0091] In this embodiment, before the capacity test, the DC resistance test is performed on the battery cell at the first state of charge value after formation, which can simplify the process of the DC resistance test.

[0092] Continuing to refer to Figure 3, optionally, the method 100 also includes: S160, converting the first DC resistance value obtained by performing a DC resistance test at the first state of charge value into a second DC resistance value at the second state of charge value, wherein the second state of charge value is located in the state of charge range at the charging end, or the second state of charge value is located in the state of charge range at the discharging end.

[0093] Research has found that when the energy storage system is at the end of charging or discharging, the uneven current phenomenon is more obvious. Therefore, the DC resistance value of the battery cell obtained at a certain SOC value at the end of charging or discharging can be selected as the basis for the subsequent assembly of battery products such as electrical boxes, cabinets or containers. Battery products can be composed of battery cells with similar DC internal resistance to ensure product consistency and avoid uneven current.

[0094] Normally, when a battery cell is charged, the SOC value changes from low to high. Specifically, when a battery cell is charged to a higher SOC value, the charging current will gradually decrease, eventually reaching a trickle charge state. At this time, the voltage of the battery cell will also gradually increase, eventually reaching the charge cut-off voltage. Therefore, the SOC value at the charging end generally refers to a high SOC value. For example, the SOC interval of the charging end of an embodiment of the present application is at least [50%, 100%], that is, the second SOC value is at least greater than 50%. In some embodiments, the SOC interval of the charging end can be the [75%, 100%] interval. The second SOC value can be 75%, 80%, 85%, 90% or 95%.

[0095] Similarly, when the battery cell is discharged, the SOC value changes from high to low. When the battery cell is discharged to a lower SOC value, the voltage of the battery cell also gradually decreases until it drops to the discharge cut-off voltage and the discharge process stops. Therefore, the SOC value at the end of discharge generally refers to a low SOC value. For example, the SOC interval at the end of discharge in the embodiment of the present application is at least [0, 50%], that is, the second SOC value is at least less than 50%. In some embodiments, the SOC interval at the end of discharge can be in the range of [10%, 25%]. The second SOC value can be 10%, 15%, 20%, 21% or 25%.

[0096] In some embodiments, the test device may internally store a conversion coefficient between a first DCR value at a first SOC value and a second DCR value at a second SOC. For example, if the first SOC value is 40% and the second SOC value is 90%, the test device internally stores a conversion coefficient for converting the DCR value at 40% SOC to the DCR value at 90% SOC. For example, if the first SOC value is 40% and the second SOC value is 21%, the test device internally stores a conversion coefficient for converting the DCR value at 40% SOC to the DCR value at 21% SOC.

[0097] Optionally, the conversion coefficient stored in the test equipment may be obtained by fitting test data obtained from DCR tests performed on a plurality of battery cells at the first SOC value and the second SOC value.

[0098] As mentioned above, when the energy storage system is at the end of charging or discharging, the uneven current phenomenon is more obvious. Usually, the SOC value of the battery cell after formation is not necessarily in the SOC range of the charging end or the SOC range of the discharging end. Therefore, directly performing DCR testing on the battery cell at the SOC value after formation and obtaining the DCR data as the basis for assembling the energy storage system cannot effectively suppress the uneven current phenomenon. Therefore, the DCR value obtained at the first SOC value of the battery cell after formation can be converted into the DCR value at the second SOC value at the charging end or the discharging end. This can greatly suppress the occurrence of uneven current phenomenon and improve the overall life of the battery product.

[0099] It should be noted that the DCR test process performed on the battery cell at the first SOC value may refer to a process of obtaining the DCR value by calculation after the battery cell is charged for a short time at the first SOC value, or may refer to a process of obtaining the DCR value by calculation after the battery cell is discharged for a short time at the first SOC value. The embodiment of the present application is not limited to this.

[0100] Optionally, as shown in Figure 4, S130, that is, performing a DC resistance test and a capacity test on the battery cell that has passed the self-discharge rate K value test and / or the aging test, includes: S132, adjusting the state of charge of the battery cell that has passed the self-discharge rate K value test and / or the aging test to a second state of charge value; S133, performing a DC resistance test on the battery cell at the second state of charge value; wherein the second state of charge value is located in the state of charge range at the charging end, or the second state of charge is located in the state of charge range at the discharging end.

[0101] Similarly, when the energy storage system is at the end of charging or discharging, the uneven current phenomenon is more obvious. Usually, the SOC value of the battery cell after formation is not necessarily in the SOC range of the charging end or the SOC range of the discharging end. Therefore, the DCR data obtained by directly performing a DCR test on the battery cell at the SOC value after formation as the basis for assembling the energy storage system cannot effectively suppress the uneven current phenomenon. Therefore, the battery cell after formation is charged or discharged to a second SOC value at the charging end or the discharging end and then the DCR test is performed. Using the DCR data obtained at the second SOC value as the basis for assembling the energy storage system cannot effectively suppress the uneven current phenomenon, thereby improving the power utilization and overall life of the battery product.

[0102] It should be understood that when the SOC value of the battery cell after formation is the second SOC value, that is, when the battery cell is directly formed to the second SOC value at the charging end or the discharging end, there is no need to adjust the SOC value of the battery cell again and the DCR test can be performed directly on the battery cell. There is no need to convert the DCR value after the test, and the DCR value under the SOC value at the charging end or the discharging end can be directly obtained, which directly simplifies the test process.

[0103] Optionally, as shown in FIG4 , S133 , performing a DC resistance test on multiple battery cells at a second state of charge value, includes: S1331 , performing a DC resistance test on the battery cells at the second state of charge value when the battery cells are left stationary for a preset time.

[0104] In other words, after the battery cell is charged or discharged to the second SOC value, the charging or discharging of the battery cell is stopped, and the battery cell is allowed to fully rest before the DC resistance test is performed on the battery cell. This allows the voltage of the battery cell to stabilize before the test, thereby further improving the accuracy of the second DCR value.

[0105] In some embodiments, the battery cell includes multiple battery cells, as shown in Figure 5, S130, that is, performing a DC resistance test and a capacity test on the multiple battery cells that have undergone the self-discharge rate K value test and / or the aging test, including: S134, performing a DC resistance test on the multiple battery cells that have undergone the self-discharge rate K value test and / or the aging test to obtain a first DC resistance value of each battery cell in the multiple battery cells; S140, that is, grading the multiple battery cells based on the results of the DC resistance test and / or the results of the capacity test, including: S141, performing time correction and / or temperature correction on the first DC resistance value of each battery cell respectively to obtain a third DC resistance value of each battery; S142, grading the multiple battery cells based on the third DC resistance values ​​of the multiple battery cells.

[0106] Generally, the DCR value of a battery cell will show an increasing trend with storage time. The battery cell needs to be stored in a warehouse for a period of time after it is produced or assembled and assembled into a battery pack. Inconsistent storage time leads to inconsistent growth of the DCR value of the battery cell. Therefore, the DCR value obtained after the battery cell is produced or assembled cannot accurately represent the DCR value when it is assembled into a battery pack. It should be understood that the first DCR value and the third DCR value in the embodiment of the present application represent DCR values ​​obtained at different times, and the time of obtaining the first DCR value is earlier than the time of obtaining the third DCR value. In addition, the third DCR value may refer to the DCR value obtained at any time after the battery cell is produced or assembled. Optionally, the first DCR value is the initial DCR value obtained by testing after the battery system is produced or assembled.

[0107] When assembling multiple battery cells into a battery pack, the control system can control the barcode scanning device to scan the identification of the battery cell to obtain the first DCR value of the battery cell. By scanning the identification of the battery cell, the time when the first DCR value of the battery cell is obtained can also be traced back. When the first DCR value is the initial DCR value, the time when the first DCR value of the battery cell is obtained can also be called the time when the battery cell was unloaded. Combined with the current time, the storage time of the battery cell can be obtained. For example, the storage time of the battery cell = current time - the time when the battery cell was unloaded. After obtaining the storage time of the battery cell and the first DCR value of the battery cell, the third DCR value of the battery cell can be calculated based on the relationship stored in the control system, which can also be called the current DCR value.

[0108] The control system may internally store a relationship between the DCR of a battery cell and the storage time of the battery cell. This relationship may be obtained by fitting a series of DCR values ​​at different storage times by the control system executing method 100, or it may be obtained from another control system. That is, the relationship may be obtained by fitting a series of DCR values ​​at different storage times by another control system and then sent by the other control system to the control system executing method 100.

[0109] Optionally, multiple mass-produced battery cells can be selected for storage in a warehouse environment, and a series of different storage days can be selected. The DCR test of the same process is performed on multiple battery cells of the same batch every n days, and the DCR values ​​of multiple battery cells of the batch with the same storage time are averaged to obtain the DCR values ​​of the battery cells with a series of different storage times. Next, the DCR values ​​of the battery cells with a series of different storage times are fitted according to "storage days, DCR value" to obtain the relationship between the DCR value of the battery cell and the storage time of the battery cell. Figure 6 shows a schematic diagram of the fitting of the DCR value of the battery cells of the same batch and the storage time of the battery cells.

[0110] In some embodiments, the DCR value of battery cells from the same batch and the storage time of the battery cells have a relationship. The DCR value of battery cells from different batches and the storage time of the battery cells may have different relationship. In other words, when performing time correction on the DCR value of a battery cell, the first DCR value of the battery cell must be determined based on the batch of the battery cell and then, based on the relationship corresponding to the batch, the storage time of the battery cell is incorporated into the relationship to determine the first DCR value of the battery cell.

[0111] In other embodiments, the DCR values ​​of battery cells from different batches tested at different storage times can also be fitted, that is, the DCR value of any batch of battery cells and the storage time of the battery cells correspond to a corresponding relationship. In other words, when correcting the DCR value of a battery cell, there is no need to determine the batch of the battery cell. The first DCR value of the battery cell can be determined directly based on the relationship stored in the control system, taking into account the storage time of the battery cell.

[0112] In addition, the DCR value of a battery cell is also temperature-dependent. The DCR values ​​of battery cells obtained at different temperatures can vary significantly and fail to reflect the true differences between battery cells. Therefore, the impact of temperature on the data needs to be removed. For example, the first DCR values ​​of different battery cells obtained at different temperatures can be corrected to a third DCR value at the same temperature, so that the differences in the third DCR values ​​of all battery cells are not affected by temperature. This same temperature can be a reference temperature, such as 25°C, or the current ambient temperature.

[0113] Similarly, the control system can store a relationship between the DCR and temperature of the battery cell. After obtaining the test temperature of the battery cell and the first DCR value at the test temperature, combined with the reference temperature or the current ambient temperature, a third DCR value of the battery cell is calculated.

[0114] In some embodiments, the DCR value of a battery cell may be corrected by first performing a time correction and then a temperature correction. For example, an initial DCR value obtained after production or assembly of the battery cell may be time-corrected, and then the time-corrected initial DCR value may be temperature-corrected to ultimately obtain a third DCR value when the battery pack is assembled.

[0115] In other embodiments, the DCR value of a battery cell may be corrected by first performing temperature correction and then performing time correction. For example, an initial DCR value obtained after production or assembly of the battery cell may be temperature corrected first, and then time corrected to obtain a third DCR value when the battery pack is assembled.

[0116] In this embodiment, the acquired first DCR value of the battery cell is time-corrected and / or temperature-corrected to obtain a third DCR value of the battery cell, which is used as a basis for DCR grading, thereby making the DCR control of the battery pack more accurate.

[0117] In one embodiment, the first DC resistance value of each battery cell may be time-corrected according to the following formula to obtain the third DC resistance value of each battery cell: R1=(aD 2 +bD+R0)*R2 / R0 (1).

[0118] Wherein, a and b are constants, R1 is the third DC resistance value of each battery cell, R2 is the first DC resistance value of each battery cell, R0 is the first DC resistance value of the reference battery cell, and D is the storage time of each battery cell.

[0119] That is to say, the first DCR value of one of the reference battery cells and the storage days of the battery cell can be obtained first, and the third DCR value of the reference battery cell can be calculated according to the fitting relationship between the DCR value and the storage days. The third DCR values ​​of other battery cells can be obtained by correcting the third DCR value of the reference battery cell. Assuming that the third DCR value of the reference battery cell is recorded as DCR3 and its first DCR value is recorded as DCR4, the third DCR value of the battery cell currently to be calculated is recorded as DCR1 and its first DCR value is recorded as DCR2, then DCR1 is obtained by calculating DCR3*DCR2 / DCR4.

[0120] It should be noted that a DCR test is usually performed immediately after the battery cell is produced or assembled, that is, a first DCR value is obtained and bound to the battery cell's identifier. After the battery cells are assembled into a battery pack, a third DCR value is immediately obtained to obtain the battery pack's DCR value and bind it to the battery pack's identifier. At the same time, the first DCR value of the battery cell can also be bound to the battery cell's identifier. Therefore, when using formula (1) to calculate the third DCR value of a battery cell, it is necessary to ensure that the reference battery cell is produced or assembled at the same time as the battery cell, and assembled into a battery pack at the same time.

[0121] In another embodiment, the first DC resistance value of each battery cell may be time-corrected according to the following formula to obtain a third DC resistance value of each battery cell: R1 = aD 2 +bD+c+R2 (2).

[0122] Wherein, a, b, and c are constants, R1 is the third DCR value of each battery cell, R2 is the first DCR value of each battery cell, and D is the storage time of each battery cell.

[0123] The third DCR value of each battery cell is obtained by using the above formula (2), which is not affected by the time when the battery cell obtains the first DCR value and the time when the battery cell is assembled into a battery pack. That is, once the first DCR value of the battery cell and its storage time are obtained, the third DCR value of the battery cell can be obtained by substituting it into the above formula (2).

[0124] In another embodiment, the first DC resistance value obtained at the test temperature may be corrected to a third DC resistance value at the reference temperature according to the following formula: R3 = f(T0) / f(T1)*R4 (3).

[0125] Wherein, R3 is the third DC resistance value, R4 is the first DC resistance value, T0 is the reference temperature, T1 is the test temperature, f(T0) and f(T1) are the values ​​obtained by substituting the reference temperature and the test temperature into the mapping function of DC resistance value and temperature, respectively.

[0126] As mentioned above, the control system can store a corresponding relationship or mapping function between DCR values ​​and temperature. This relationship or mapping function can be obtained through data fitting. For example, for a battery pack composed of battery cells, the DCR test values ​​and corresponding test temperatures of all battery cells on the production line over the past month can be collected. The DCR test values ​​of all battery cells are then fitted with the test temperatures to obtain the mapping function between DCR values ​​and temperature.

[0127] After obtaining the test temperature T1, the first DCR value R4 and the reference temperature T0 of the battery cell, the control system can first substitute T1 and T0 into the mapping function of the DCR value and temperature, and then substitute them into the above formula (3), and then the third DCR value R4 of the battery cell can be calculated.

[0128] In some embodiments, as shown in FIG7 , S142 , i.e., grading a plurality of battery cells based on the third DC resistance value of each battery cell, includes: S1421 , assembling N battery cells into a battery pack when the sum of the third DC resistance values ​​of N battery cells among the plurality of battery cells is within a first preset range, where N is a positive integer greater than 1.

[0129] It should be noted that N battery cells are connected in series to form a battery pack. A battery cell may be a minimum unit or not. For example, N battery cells are N battery cells, and N battery cells are connected in series to form an electrical box. Then, it is necessary to determine whether the cumulative sum of the third DCR values ​​of N battery cells among the multiple battery cells is within the first preset range. If the cumulative sum of the third DCR values ​​of the N battery cells is within the first preset range, the N battery cells are assembled into an electrical box. For another example, N battery cells are N battery modules, each battery module is formed by at least two battery cells connected in parallel, and N battery modules are connected in series to form an electrical box. Then, it is necessary to determine whether the cumulative sum of the third DCR values ​​of the N battery modules is within the first preset range. If the cumulative sum of the third DCR values ​​of the N battery modules is within the first preset range, the N battery modules are assembled into an electrical box.

[0130] Optionally, after obtaining the first DCR value of each battery cell, time correction and / or temperature correction may not be performed on it, and it may be directly determined whether the cumulative sum of the first DCR values ​​of N battery cells is within a first preset range. If the cumulative sum of the first DCR values ​​of the N battery cells is within the first preset range, the N battery cells are assembled.

[0131] The first preset range may be a DCR control range set before assembling the battery pack. For example, the DCR control range is [DCR 下限 , DCR 上限 ]. When assembling the battery pack, the control system can control the barcode scanning device to scan the identification of each battery cell and obtain the first DCR value of each battery cell, and perform time correction and / or temperature correction on the first DCR value to obtain the third DCR value of each battery cell. The control system can sequentially accumulate the third DCR values ​​of N battery cells. If the cumulative sum of the third DCR values ​​of the N battery cells belongs to [DCR 下限 , DCR 上限 ], the N battery cells are assembled normally and packed into the warehouse.

[0132] In this embodiment, when assembling a battery pack, a DCR control range of the battery pack is given, and the N battery cells are assembled into a battery pack only when the sum of the third DCR values ​​of the N battery cells is monitored to be within the DCR control range. This method has simple control steps and is easy to operate. It is also beneficial to improving the consistency of DCR between battery packs, reducing the probability of uneven current during the charging or discharging process, and ultimately extending the life of the product.

[0133] In some embodiments, the N battery cells are continuously fed into an assembly line.

[0134] In other embodiments, at least two adjacent battery cells among the N battery cells do not enter the assembly line continuously.

[0135] Typically, when assembling battery cells into a battery pack, the battery cells enter the assembly line in sequence, that is, the battery cells are conveyed on the conveyor belt in sequence. In an embodiment of the present application, the control system can monitor each battery cell entering the assembly line and first calculate the cumulative sum of the third DCR values ​​of N consecutive battery cells. If the cumulative sum of the third DCR values ​​of the N consecutive battery cells meets the DCR control range, the N consecutive battery cells can be directly assembled into a battery pack. If the cumulative sum of the third DCR values ​​of the N consecutive battery cells does not meet the DCR control range, some of the N consecutive battery cells can be replaced until the cumulative sum of the third DCR values ​​of the new N battery cells is within the DCR control range, and the new N battery cells are assembled into a battery pack. Since some of the new N battery cells are replaced by other battery cells, the new N battery cells assembled into the battery pack are not completely continuous.

[0136] For example, as shown in FIG8 , taking an electrical cabinet composed of electrical boxes as an example, one electrical cabinet requires eight electrical boxes. The control system monitors the electrical boxes entering the assembly line and accumulates the sum of the third DCR values ​​of the 8 electrical boxes in real time. When the cumulative sum of the third DCR values ​​of the 8 electrical boxes in the first round (electrical box 1, electrical box 2, electrical box 3, electrical box 4, electrical box 5, electrical box 6, electrical box 7 and electrical box 8) meets the DCR control range, the 8 electrical boxes in the first round are directly assembled into an electrical cabinet and enter the electrical cabinet stacking area. When the cumulative sum of the third DCR values ​​of the 8 electrical boxes in the first round does not meet the DCR control range, the cumulative sum of the third DCR values ​​of the 8 electrical boxes in the second round can be performed. The 8 electrical boxes in the second round can include the last 7 electrical boxes in the 8 electrical boxes in the first round and the first electrical box after the 8 electrical boxes in the first round. For example, the 8 electrical boxes in the second round include electrical box 2, electrical box 3, electrical box 4, electrical box 5, electrical box 6, electrical box 7, electrical box 8 and electrical box 9. It should be noted that electrical boxes 1 to 8 in the electrical cabinet stacking area are only used to illustrate the number of electrical boxes included in an electrical cabinet, and do not specifically refer to electrical boxes 1 to 8 that enter the assembly line in sequence. In addition, while judging whether the cumulative sum of the third DCR values ​​of the 8 electrical boxes in the second round (electrical box 2, electrical box 3, electrical box 4, electrical box 5, electrical box 6, electrical box 7, electrical box 8 and electrical box 9) meets the DCR control range, control electrical box 1 among the 8 electrical boxes in the first round to enter the abnormal battery cell channel, and this abnormal battery cell channel directly leads to the assembly line. Then, electrical box 1 that passes through the abnormal battery cell channel can enter the assembly line again and be re-monitored by the control system.

[0137] It should be understood that the above description is only based on the example of controlling the smallest electric box 1 among the first round of 8 electric boxes entering the assembly line to enter the abnormal battery cell channel when the sum of the third DCR values ​​of the 8 electric boxes in the first round does not meet the DCR control range. However, those skilled in the art will understand that any one of the 8 electric boxes in the first round or any multiple electric boxes can be controlled to enter the abnormal battery channel. For example, it can be the electric box 8 that is the last one to enter the assembly line among the 8 electric boxes in the first round to enter the abnormal battery cell channel, or it can be the electric box that is closest to the abnormal battery cell channel among the 8 electric boxes in the first round. The embodiments of the present application do not limit this.

[0138] In another embodiment, as shown in FIG7 , S142, i.e., grading the plurality of battery cells based on the third DC resistance value of each battery cell, includes: S1422, when the third DC resistance value of each battery cell in N battery cells among the plurality of battery cells is within a second preset range, assembling the N battery cells into a battery pack, where N is a positive integer greater than 1.

[0139] Specifically, before assembling the battery cells into a battery pack, at least one preset DCR range for grading the battery cells can be pre-defined. After obtaining the third DCR value of each battery cell, the range to which the third DCR value of each battery cell belongs can be determined one by one, and then N battery cells belonging to the same range can be assembled into a battery pack.

[0140] Taking battery cells assembled into an electrical box as an example, three DCR preset ranges can be set, corresponding to S gear, T gear, and U gear, from low to high. After obtaining the third DCR value of a battery cell, the control system can first determine whether the battery cell belongs to the S gear. If so, the battery cell is marked as S gear or placed in a fixed position belonging to the S gear. If not, the control system can continue to determine whether the battery cell belongs to the T gear. If so, the battery cell is marked as T gear or placed in a fixed position belonging to the T gear. If not, the control system can continue to determine whether the battery cell belongs to the U gear. If so, the battery cell is marked as U gear or placed in a fixed position belonging to the U gear. If not, the battery cell is placed in the scrap area. Each battery cell can be graded according to this process. Whenever there are eight battery cells belonging to the same gear, the eight battery cells are directly assembled into an electrical box, and the electrical box can also be marked with the same gear as the battery cell, so that the electrical boxes belonging to the same gear can be assembled into an electrical cabinet later. Similarly, the electrical cabinet can also be marked with the same gear as the electrical box, so that the electrical cabinets belonging to the same gear can be assembled into a container later. In this way, the consistency of DCR between electrical cabinets can be improved, and ultimately the life of the container can be extended.

[0141] In this embodiment, each battery cell is categorized according to its third DCR value, and finally N battery cells belonging to the same tier are assembled into a battery pack. This method has simple control steps, is easy to operate, and can also improve the consistency of DCR between battery cells in the battery pack.

[0142] Optionally, after obtaining the first DCR value of each battery cell, time correction and / or temperature correction may not be performed on it, and it may be directly determined whether the first DCR value of each battery cell is within the second preset range. If the first DCR value of each battery cell in the N battery cells is within the first preset range, the N battery cells are assembled.

[0143] In some embodiments, as shown in FIG7 , the method 100 further includes: S170 , determining a DC resistance value of the battery pack according to a third DC resistance value of each battery cell in the N battery cells.

[0144] Determining the DCR value of the battery pack based on the third DCR value of each battery cell means that the DCR value of the battery pack is calculated based on the third DCR value of each battery cell. For example, the DCR value of the battery pack is equal to the sum of the third DCR values ​​of all battery cells included in the battery pack. For another example, the DCR value of the battery pack includes at least the sum of the third DCR values ​​of all battery cells included in the battery pack.

[0145] Similarly, when determining the DCR value of the battery pack, calculation may also be performed based on the first DCR value of each battery cell, which is not limited in the embodiment of the present application.

[0146] In this embodiment, the DCR value of the battery pack can be calculated based on the third DCR value of each battery cell in the multiple battery cells, eliminating the need for DCR testing of the battery pack, saving production line equipment costs and improving production capacity. In addition, obtaining the DCR value of each battery cell also helps to understand the balance within the battery pack, thereby improving the performance of the entire battery pack.

[0147] In some embodiments, the battery pack also includes a connecting component, as shown in Figure 7, S170, that is, determining the DC resistance value of the battery pack based on the third DC resistance value of each battery cell in the N battery cells, including: S171, determining the sum of the third DC resistance values ​​of the N battery cells and the sum of the resistance value of the connecting component as the DC resistance value of the battery pack.

[0148] In other words, for a battery pack, the DCR value of the battery pack can be decomposed into the DCR value of the battery cell part and the resistance value of other connecting components. Optionally, the connecting components in the battery pack may include at least one of a busbar, a fuse, a high-voltage wiring harness, and a switch. For example, if the battery pack is an electrical box, the electrical box may be formed by connecting multiple battery cells via a busbar so that electrical energy can be transmitted between the multiple battery cells. The electrical box also includes a fuse and a manual maintenance switch to protect the circuit and prevent abnormal conditions such as overcurrent or overheating from damaging the electrical box. For another example, if the battery pack is an electrical cabinet, the electrical cabinet may be composed of multiple electrical boxes connected by a high-voltage wiring harness and various functional connecting components in the main control box. For example, the functional connecting components may include a busbar, a fuse, an isolating switch, a circuit breaker, a current sensor, and a connector.

[0149] In this embodiment, the DCR value of the battery pack is determined as the sum of the third DCR values ​​of the N battery cells and the resistance value of the connecting component. On the one hand, the resistance of the connecting component is taken into account, which improves the accuracy of the DC internal resistance of the battery pack compared to directly using the DC internal resistance of the N battery cells as the DC internal resistance of the battery pack. On the other hand, compared to obtaining the DC internal resistance of the battery pack through testing, it can save production line equipment costs and improve production capacity.

[0150] Optionally, the battery pack is a battery box, and the battery unit is a battery cell.

[0151] In one embodiment, as shown in FIG9 , the electrical box is formed by N battery cells connected in series, wherein one battery cell is divided into a group of battery cells. Assume that the first DCR value of battery cell 1 is DCR1, the first DCR value of battery cell 2 is DCR2, and so on. The first DCR value of battery cell N is DCR N The DCR value of N battery cells can be calculated using the following formula: x = DCR1 + DCR2 + ... + DCR N (4).

[0152] In another embodiment, as shown in FIG10 , the electric box is formed by connecting N groups of battery cells in series, and each group of battery cells is formed by connecting two battery cells in parallel. Assuming that the first DCR value of battery cell 1 is DCR1, the first DCR value of battery cell 2 is DCR2, and so on, the first DCR value of battery cell 2N-1 is DCR 2,N-1 , the first DCR value of battery cell 2N is DCR 2N Then the DCR value of 2N battery cells can be calculated using the following formula:

[0153] In other embodiments, the battery pack is a power cabinet or a battery cluster, and the battery unit is a power box. For example, the power cabinet or battery cluster includes N power boxes connected in series, and the sum of the DCR values ​​of the N power boxes can be calculated using the above formula (4).

[0154] In some embodiments, the resistance value of the connection component can be determined according to the following formula: z=R5(1+αT) (6).

[0155] Where α is the temperature coefficient of the connection component, R5 is the test value of the connection component, and T is the current ambient temperature.

[0156] For example, the test value R5 of the busbar component in the electrical box is measured at room temperature of 25°C. The temperature is adjusted to obtain the resistance value z of the busbar component at different temperatures. The resistance value z and temperature T at different temperatures are fitted to obtain the temperature coefficient α of the busbar component, as shown in Figure 11. In a similar way, the temperature coefficients of other connecting components in the electrical box can also be obtained. According to the ambient temperature during assembly of the electrical box production line and the test values ​​of each connecting component, the above formula (6) is substituted into the above formula to obtain the calibrated resistance values ​​of other connecting components except the battery cell. Finally, when calculating the DCR value of the electrical box, the calibrated resistance values ​​of all connecting components need to be added together to obtain the resistance value z of the connecting components in the electrical box.

[0157] In some embodiments, as shown in FIG5 , the method 100 further includes: S180 , storing the correspondence between the first DC resistance values ​​of the plurality of battery cells and their respective identifiers in at least one of a manufacturing execution system, a battery management system, a cloud server, and a local database.

[0158] For example, after obtaining the first DCR value of a battery cell, the first DCR value of the battery cell can be uploaded to at least one of a manufacturing execution system (MES), a battery management system (BMS), a cloud server, and a local database to achieve binding between the identification of the battery cell and the first DCR value. Subsequently, when calculating the DCR value of an electrical box or even an electrical cabinet, the DCR value of each battery cell can be traced back. In this way, the DCR value of the electrical box or the DCR value of the electrical cabinet can be calculated based on the DCR value of the battery cell, without the need to perform a DCR test on the electrical box or the electrical cabinet, thereby saving testing costs.

[0159] The battery binning method according to an embodiment of the present application is described in detail above. The battery binning device according to an embodiment of the present application will be described in detail below with reference to Figures 12 to 14. The technical features described in the method embodiment are applicable to the following device embodiments.

[0160] Figure 12 shows a schematic block diagram of a battery manufacturing apparatus 200 according to an embodiment of the present application. As shown in Figure 12, the apparatus 200 includes some or all of the following contents.

[0161] The formation unit 210 is used to perform formation processing on the battery cells.

[0162] The K value test and / or aging test unit 220 is used to perform a self-discharge rate K value test and / or an aging test on the battery cells that have undergone the formation process, so as to stabilize the voltage of the battery cells.

[0163] The DC resistance test and capacity test unit 230 is used to perform a DC resistance test and a capacity test on the battery cells that have passed the self-discharge rate K value test and / or the aging test.

[0164] The grading unit 240 is configured to grade the battery cells based on the results of the DC resistance test and / or the capacity test.

[0165] In one embodiment, the formation unit 210 is specifically used to: form the battery cell to a first state of charge value; the DC resistance test and capacity test unit 230 is specifically used to: perform a DC resistance test on the battery cell that has undergone the self-discharge rate K value test and / or aging test at the first state of charge value.

[0166] In one embodiment, as shown in Figure 13, the device 200 also includes: a conversion unit 260, which is used to convert a first DC resistance value obtained by performing a DC resistance test at a first state of charge value into a second DC resistance value at a second state of charge value; wherein the second state of charge value is located in the state of charge range at the charging end, or the second state of charge value is located in the state of charge range at the discharging end.

[0167] In one embodiment, the DC resistance test and capacity test unit 230 is specifically used to: adjust the state of charge of the battery cell that has undergone the self-discharge rate K value test and / or aging test to a second state of charge value; and perform a DC resistance test on the battery cell at the second state of charge value; wherein the second state of charge value is located in the state of charge range at the charging end, or the second state of charge is located in the state of charge range at the discharging end.

[0168] In one embodiment, the DC resistance and capacity testing unit 230 is specifically configured to perform a DC resistance test on the battery cell at the second state of charge value when the battery cell is left at rest for a preset time period.

[0169] In one embodiment, the state of charge interval at the charging end is [75%, 100%], and / or the state of charge interval at the discharging end is [10%, 25%].

[0170] In one embodiment, the battery cell includes multiple battery cells, and the DC resistance test and capacity test unit 230 is specifically used to: perform a DC resistance test on multiple battery cells that have undergone a self-discharge rate K value test and / or an aging test to obtain a first DC resistance value of each battery cell in the multiple battery cells; the grading unit 240 is specifically used to: perform time correction and / or temperature correction on the first DC resistance value of each battery cell respectively to obtain a third DC resistance value of each battery cell; and grade the multiple battery cells based on the third DC resistance values ​​of the multiple battery cells.

[0171] In one embodiment, the grading unit 240 is specifically used to assemble N battery cells into a battery pack when the sum of the third DC resistance values ​​of N battery cells in the plurality of battery cells is within a first preset range, where N is a positive integer greater than 1.

[0172] In one embodiment, the grading unit 240 is specifically used to assemble N battery cells in a plurality of battery cells into a battery pack when the third DC resistance value of each battery cell is within a second preset range, where N is a positive integer greater than 1.

[0173] In one embodiment, as shown in FIG13 , the apparatus 200 further includes: a determining unit 270 configured to determine a DC resistance value of the battery pack according to a third DC resistance value of each battery cell in the N battery cells.

[0174] In one embodiment, the battery pack further includes a connecting component, and the determining unit 270 is specifically configured to determine the DC resistance value of the battery pack as the sum of the third DC resistance values ​​of the N battery cells and the sum of the resistance value of the connecting component.

[0175] In one embodiment, the battery unit is a battery cell, and the battery pack is an electrical box; or, the battery unit is an electrical box, and the battery pack is an electrical cabinet.

[0176] In one embodiment, as shown in FIG13 , the apparatus 200 further includes: a storage unit 280 for storing the correspondence between the first DC resistance values ​​of the plurality of battery cells and their respective identifiers in at least one of a manufacturing execution system, a battery management system, a cloud server, and a local database.

[0177] It should be understood that the above-mentioned modules in the device 200 are used to implement the corresponding processes in the various methods in Figures 2 to 11. For the sake of brevity, they are not repeated here.

[0178] Figure 14 shows a schematic block diagram of a control system 300 according to an embodiment of the present application. As shown in Figure 14, the control system 300 includes a processor 310 and a memory 320, wherein the memory 320 is used to store instructions, and the processor 310 is used to read the instructions and execute the methods of the various embodiments of the present application described above based on the instructions.

[0179] The memory 320 may be a separate device independent of the processor 310 , or may be integrated into the processor 310 .

[0180] Optionally, as shown in Figure 14, the control system 300 may further include a transceiver 330, and the processor 310 may control the transceiver 330 to communicate with other devices, specifically, to send information or data to other devices, or to receive information or data sent by other devices.

[0181] It should be understood that the processor of the embodiments of the present application may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiment can be completed by hardware integrated logic circuits in the processor or software instructions. The above processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The various methods, steps, and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in the embodiments of the present application can be directly embodied as being executed by a hardware decoding processor, or can be executed by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium mature in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0182] It is understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct RAM bus random access memory (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0183] An embodiment of the present application also provides a computer-readable storage medium for storing a computer program.

[0184] Optionally, the computer-readable storage medium can be applied to the control system in the embodiments of the present application, and the computer program enables the computer to execute the corresponding processes implemented by the control system in the various methods of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0185] An embodiment of the present application also provides a computer program product, including computer program instructions.

[0186] Optionally, the computer program product can be applied to the control system in the embodiments of the present application, and the computer program instructions enable the computer to execute the corresponding processes implemented by the control system in the various methods of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0187] The embodiment of the present application also provides a computer program.

[0188] Optionally, the computer program can be applied to the control system in the embodiments of the present application. When the computer program runs on a computer, the computer executes the corresponding processes implemented by the control system in the various methods of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0189] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0190] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0191] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0192] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, 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. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a ROM, a RAM, a magnetic disk, or an optical disk.

[0193] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for manufacturing a battery, characterized in that: include: Performing formation treatment on battery cells; Performing a self-discharge rate K value test and / or an aging test on the battery cell that has undergone the formation treatment to stabilize the voltage of the battery cell; Performing a DC resistance test and a capacity test on the battery cell that has undergone the self-discharge rate K value test and / or the aging test; The battery cells are categorized based on the results of the DC resistance test and / or the results of the capacity test.

2. The method according to claim 1, characterized in that The forming treatment of the battery cell comprises: charging the battery cell to a first state of charge value; The performing of a DC resistance test and a capacity test on the battery cell that has undergone the self-discharge rate K value test and / or the aging test comprises: Under the first state of charge value, a DC resistance test is performed on the battery cell that has passed the self-discharge rate K value test and / or the aging test.

3. The method according to claim 2, characterized in that The method further comprises: converting a first DC resistance value obtained by performing a DC resistance test at the first state of charge value into a second DC resistance value at a second state of charge value; The second state of charge value is located in the state of charge interval at the charging end, or the second state of charge value is located in the state of charge interval at the discharging end.

4. The method according to claim 1, wherein The performing of a DC resistance test and a capacity test on the battery cell that has undergone the self-discharge rate K value test and / or the aging test comprises: Adjusting the state of charge of the battery cell that has undergone the self-discharge rate K value test and / or the aging test to a second state of charge value; performing a DC resistance test on the battery cell at the second state of charge value; The second state of charge value is located in the state of charge range at the charging end, or the second state of charge is located in the state of charge range at the discharging end.

5. The method according to claim 4, characterized in that The step of performing a DC resistance test on the battery cell at the second state of charge value includes: When the battery cell is left at rest for a preset time, a DC resistance test is performed on the battery cell at the second state of charge value.

6. The method according to any one of claims 3 to 5, characterized in that The state of charge interval of the charging terminal is [75%, 100%], and / or the state of charge interval of the discharging terminal is [0%, 25%].

7. The method according to any one of claims 1 to 6, characterized in that The battery cell includes a plurality of battery cells, and the DC resistance test and the capacity test are performed on the battery cells that have undergone the self-discharge rate K value test and / or the aging test, including: The DC resistance test is performed on the plurality of battery cells that have undergone the self-discharge rate K value test and / or the aging test to determine the Obtaining a first DC resistance value of each battery cell in the plurality of battery cells; The grading of the plurality of battery cells based on the result of the DC resistance test and / or the result of the capacity test includes: Performing time correction and / or temperature correction on the first DC resistance value of each battery cell respectively to obtain a third DC resistance value of each battery cell; The plurality of battery cells are divided into bins based on the third DC resistance values of the plurality of battery cells.

8. The method according to claim 7, characterized in that The step of grading the plurality of battery cells based on the third DC resistance values of the plurality of battery cells includes: When the sum of the third DC resistance values of N battery cells among the plurality of battery cells is within a first preset range, the N battery cells are assembled into a battery pack, where N is a positive integer greater than 1.

9. The method according to claim 7, characterized in that The step of grading the plurality of battery cells based on the third DC resistance values of the plurality of battery cells includes: When the third DC resistance value of each of N battery cells in the plurality of battery cells is within a second preset range, the N battery cells are assembled into a battery pack, where N is a positive integer greater than 1.

10. The method according to claim 8 or 9, characterized in that The method further comprises: The DC resistance value of the battery pack is determined according to the third DC resistance value of each battery cell in the N battery cells.

11. The method according to claim 10, characterized in that The battery pack further includes a connecting component, and determining the DC resistance value of the battery pack according to the third DC resistance value of each of the N battery cells includes: The sum of the third DC resistance values of the N battery cells and the resistance value of the connecting component is determined as the DC resistance value of the battery pack.

12. The method according to any one of claims 8 to 11, characterized in that The battery unit is a battery monomer, and the battery pack is an electrical box; or, the battery unit is an electrical box, and the battery pack is an electrical cabinet.

13. The method according to any one of claims 7 to 12, characterized in that The method further comprises: The correspondence between the first DC resistance values of the plurality of battery cells and their respective identifiers is stored in at least one of a manufacturing execution system, a battery management system, a cloud server, and a local database.

14. A device for manufacturing a battery, characterized in that: include: A formation unit, used for performing formation treatment on the battery cells; A K value test and / or aging test unit, configured to perform a self-discharge rate K value test and / or an aging test on the battery cell that has undergone formation treatment, so as to stabilize the voltage of the battery cell; A DC resistance test and capacity test unit, used to perform a DC resistance test and a capacity test on the battery cell that has undergone the self-discharge rate K value test and / or the aging test; A grading unit is used to grade the battery cells based on the result of the DC resistance test and / or the result of the capacity test.

15. The device according to claim 14, characterized in that The formation unit is specifically used for: charging the battery cell to a first state of charge value; The DC resistance test and capacity test unit is specifically used for: Under the first state of charge value, the battery cell that has undergone the self-discharge rate K value test and / or aging test Perform a DC resistance test.

16. The device according to claim 15, characterized in that The device further comprises: a conversion unit, configured to convert a first DC resistance value obtained by performing a DC resistance test at the first state of charge value into a second DC resistance value at a second state of charge value; The second state of charge value is located in the state of charge interval at the charging end, or the second state of charge value is located in the state of charge interval at the discharging end.

17. The device according to claim 14, characterized in that The DC resistance test and capacity test unit is specifically used for: Adjusting the state of charge of the battery cell that has undergone the self-discharge rate K value test and / or the aging test to a second state of charge value; performing a DC resistance test on the battery cell at the second state of charge value; The second state of charge value is located in the state of charge range at the charging end, or the second state of charge is located in the state of charge range at the discharging end.

18. The device according to claim 17, characterized in that The DC resistance test and capacity test unit is specifically used for: When the battery cell is left at rest for a preset time, a DC resistance test is performed on the battery cell at the second state of charge value.

19. The device according to any one of claims 16 to 18, characterized in that The state of charge interval of the charging terminal is [75%, 100%], and / or the state of charge interval of the discharging terminal is [10%, 25%].

20. The device according to any one of claims 14 to 19, characterized in that The battery unit includes a plurality of battery cells, and the DC resistance test and capacity test unit is specifically used for: Performing a DC resistance test on the plurality of battery cells that have undergone the self-discharge rate K value test and / or the aging test to obtain a first DC resistance value of each battery cell in the plurality of battery cells; The binning unit is specifically used for: Performing time correction and / or temperature correction on the first DC resistance value of each battery cell respectively to obtain a third DC resistance value of each battery cell; The plurality of battery cells are divided into bins based on the third DC resistance values of the plurality of battery cells.

21. The device according to claim 20, characterized in that The binning unit is specifically used for: When the sum of the third DC resistance values of N battery cells among the plurality of battery cells is within a first preset range, the N battery cells are assembled into a battery pack, where N is a positive integer greater than 1.

22. The device according to claim 20, characterized in that The binning unit is specifically used for: When the third DC resistance value of each of N battery cells in the plurality of battery cells is within a second preset range, the N battery cells are assembled into a battery pack, where N is a positive integer greater than 1.

23. The device according to claim 21 or 22, characterized in that The device further comprises: A determining unit is configured to determine a DC resistance value of the battery pack according to the third DC resistance value of each battery cell in the N battery cells.

24. The device according to claim 23, characterized in that The battery pack further includes a connecting component, and the determining unit is specifically configured to: The sum of the third DC resistance values of the N battery cells and the resistance value of the connecting component is determined as is the DC resistance of the battery pack.

25. The device according to any one of claims 21 to 24, characterized in that The battery unit is a battery monomer, and the battery pack is an electrical box; or, the battery unit is an electrical box, and the battery pack is an electrical cabinet.

26. The device according to any one of claims 20 to 25, characterized in that The device further comprises: A storage unit is used to store the corresponding relationship between the first DC resistance values of the multiple battery cells and their respective identifiers in at least one of a manufacturing execution system, a battery management system, a cloud server, and a local database.

27. A control system, characterized in that: include: a memory for storing instructions; A processor, configured to read the instruction and execute the method according to any one of claims 1 to 13 according to the instruction.

Images