Apparatus and method for battery discharge for transport

Abstract

An apparatus for discharging a battery for transportation according to an embodiment of the present invention may comprise: a charging and discharging unit connected to one or more battery cells and performing charging or discharging on the one or more battery cells; a measurement unit that provides a relevant measurement value measured by monitoring each battery cell to the controller; and a control unit that controls the charging and discharging unit to perform a first discharge on the one or more battery cells in accordance with a first current value with reference to a pre-configured discharge capacity, and to perform a second discharge on the one or more battery cells in accordance with a second current value with reference to a pre-configured voltage, the second current value changes according to a specific time interval.

Description

Technical Field

[0001] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0012727 filed in the Korean Intellectual Property Office on January 31, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to an apparatus and method for pre-shipment discharge of a battery, and more particularly, to an apparatus and method for performing pre-shipment discharge of one or more battery cells using multiple discharge steps. Background Art

[0003] A secondary battery is a battery that can be recharged and reused even after being discharged. Secondary batteries can be used as energy sources for small devices such as mobile phones, tablet PCs, and vacuum cleaners, and can also be used as energy sources for medium and large devices such as automobiles and energy storage systems (ESS) for smart grids. Depending on system requirements, secondary batteries are applied to systems in the form of components such as battery modules in which a plurality of battery cells are connected in series and in parallel or battery packs in which battery modules are connected in series and in parallel.

[0004] Batteries can be roughly classified into cylindrical, pouch, and prismatic types according to their shapes. These batteries are the same in that they are manufactured by combining a separator and an electrolyte after manufacturing a positive plate and a negative plate, but they can have different shapes depending on how they are assembled and packaged.

[0005] Generally, a battery can be manufactured through an electrode process, an assembly process, an activation (forming) process, and a packaging process. Among these processes, in the activation process, charging and discharging operations are repeatedly performed to activate the battery cell. The charging and discharging operations take a lot of time, and the charging and discharging time is proportional to the investment cost of the charging and discharging device, so it has a significant impact on the profitability of the battery.

[0006] In addition, among the charging and discharging operations required during the activation process, pre-shipment charging or pre-shipment discharging is performed just before the battery is shipped. Pre-shipment charging has a problem of increased charging time, and pre-shipment discharging has a problem of increased voltage deviation between batteries. Therefore, a charging or discharging method that can improve voltage deviation and shorten charging and discharging process time is required. Summary of the invention

[0007] Technical issues

[0008] To obviate one or more problems of the related art, embodiments of the present disclosure provide a battery pre-shipment discharge apparatus for performing pre-shipment discharge of one or more battery cells.

[0009] To obviate one or more problems of the related art, embodiments of the present disclosure also provide a method for performing pre-shipment discharge of one or more battery cells.

[0010] Technical Solution

[0011] To achieve the purpose of the present disclosure, a device for performing pre-transport discharge of one or more battery cells may include: a charger-discharger connected to the one or more battery cells and configured to charge or discharge the one or more battery cells; a measuring unit configured to monitor each battery cell and provide relevant measurement values ​​to a controller; and a controller configured to control the charger-discharger to perform a first discharge stage on the one or more battery cells according to a first current value based on a predetermined discharge capacity, and to perform a second discharge stage on the one or more battery cells according to a second current value based on a predetermined voltage, the second current value varying according to a specific time period, wherein the controller controls the charger-discharger to perform the first discharge stage and the second discharge stage before transporting the one or more battery cells.

[0012] Here, in a case where the predetermined discharge capacity is reached while the first discharge stage is performed, the controller may terminate the first discharge stage.

[0013] In addition, in a case where the voltage of each battery cell reaches the predetermined voltage when the second discharging stage is performed, the controller may terminate the second discharging stage of each battery cell.

[0014] The first current value may be greater than the second current value.

[0015] The second discharge phase may include three or more specific discharge steps using the same or different charge and discharge rates.

[0016] A charge / discharge rate of a temporally last specific discharge step among three or more specific discharge steps included in the second discharge stage may be determined to have a value smaller than charge / discharge rates applied to the remaining specific discharge steps.

[0017] For example, the second discharge stage may include: a first specific discharge step of performing discharge using a first charge / discharge rate; a second specific discharge step of performing discharge using a second charge / discharge rate; a third specific discharge step of performing discharge using a third charge / discharge rate; a fourth specific discharge step of performing discharge using a fourth charge / discharge rate; and a fifth specific discharge step of performing discharge using a fifth charge / discharge rate.

[0018] According to an example, the first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, and the fourth charge / discharge rate are determined to be the same value, and the fifth charge / discharge rate is determined to be less than the first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, and the fourth charge / discharge rate.

[0019] According to another example, the first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, the fourth charge / discharge rate, and the fifth charge / discharge rate are determined to be different values ​​that decrease in sequence. Here, the third charge / discharge rate can be determined based on the first charge / discharge rate and the fifth charge / discharge rate.

[0020] Additionally, the controller fully charges the one or more battery cells before executing the first discharge phase.

[0021] According to another embodiment of the present disclosure, a method for performing pre-transportation discharge of one or more battery cells may include the following steps: performing a first discharge stage on the one or more battery cells according to a first current value based on a predetermined discharge capacity; and performing a second discharge stage on the one or more battery cells according to a second current value based on a predetermined voltage, wherein the second current value varies according to a specific time period, wherein the first discharge stage and the second discharge stage are performed before transporting the one or more battery cells.

[0022] Performing the first discharge stage may include: terminating the first discharge stage in a case where the predetermined discharge capacity is reached while performing the first discharge stage.

[0023] The performing of the second discharge stage may include: terminating the second discharge stage of each battery cell when the voltage of each battery cell reaches the predetermined voltage during the performing of the second discharge stage.

[0024] The first current value may be greater than the second current value.

[0025] The second discharge phase may include three or more specific discharge steps using the same or different charge and discharge rates.

[0026] A charge / discharge rate of a temporally last specific discharge step among three or more specific discharge steps included in the second discharge stage may be determined to have a value smaller than charge / discharge rates applied to the remaining specific discharge steps.

[0027] For example, the second discharge stage may include: a first specific discharge step of performing discharge using a first charge / discharge rate; a second specific discharge step of performing discharge using a second charge / discharge rate; a third specific discharge step of performing discharge using a third charge / discharge rate; a fourth specific discharge step of performing discharge using a fourth charge / discharge rate; and a fifth specific discharge step of performing discharge using a fifth charge / discharge rate.

[0028] According to an example, the first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, and the fourth charge / discharge rate may be determined to be the same value, and the fifth charge / discharge rate may be determined to be less than the first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, and the fourth charge / discharge rate.

[0029] According to another example, the first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, the fourth charge / discharge rate, and the fifth charge / discharge rate may be determined as different values ​​that decrease in sequence. Here, the third charge / discharge rate may be determined based on the first charge / discharge rate and the fifth charge / discharge rate.

[0030] Furthermore, the method may further comprise: fully charging the one or more battery cells before performing the first discharging phase.

[0031] Beneficial Effects

[0032] According to the battery pre-shipment discharging method according to the embodiment of the present invention as described above, voltage dispersion between battery cells can be improved, and a processing time required for battery pre-shipment discharging can be shortened.

[0033] Therefore, the effects of reducing the investment cost of the charging and discharging device and improving the power cost of the activation process can be expected. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic diagram of a battery manufacturing process to which the present invention may be applied.

[0035] Figure 2 The concept of a general 1-step constant-current discharge method, the flow of current used in the general 1-step constant-current discharge method, and voltage changes during the general 1-step constant-current discharge process are shown.

[0036] Figure 3 The concept of the pre-shipment discharge method according to the embodiment of the present invention, the flow of current used in the pre-shipment discharge method according to the embodiment of the present invention, and the voltage change during the pre-shipment discharge process according to the embodiment of the present invention are shown.

[0037] Figure 4 is a block diagram of a pre-shipment discharge device according to an embodiment of the present invention.

[0038] Figure 5 An operation sequence of a method for discharging a battery before shipping according to an embodiment of the present invention is shown.

[0039] Figure 6 Experimental parameters and test results for deriving an optimal pre-shipment discharge treatment according to the present invention are shown.

[0040] Figure 7 Test results of several experimental examples according to different experimental parameters for deriving an optimal pre-shipment discharge treatment according to the present invention are shown.

[0041] Figure 8 The verification results of the optimal pre-transportation discharge method as a preferred embodiment according to the present invention are shown.

[0042] 100: Discharge equipment before transportation 110: Controller

[0043] 120: Charger / discharger 130: Measurement unit DETAILED DESCRIPTION

[0044] The present invention can be modified in various forms and has various embodiments, and its specific embodiments are shown in the drawings by way of example and will be described in detail below. However, it should be understood that it is not intended to limit the present invention to specific embodiments, but on the contrary, the present invention will cover all modifications, equivalents and alternative forms that fall within the spirit and technical scope of the present invention. Throughout the description of the drawings, the same reference numerals refer to the same elements.

[0045] It will be understood that although various elements may be described herein using terms such as "first", "second", A, B, etc., these elements should not be limited by these terms. These terms are simply used to distinguish one element from another. For example, without departing from the scope of the present invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. As used herein, the term "and / or" includes a combination of multiple associated listed items or any one of multiple associated listed items.

[0046] It will be understood that when an element is referred to as being "coupled" or "connected" to another element, it can be directly coupled or connected to the other element, or there can be intervening elements. Conversely, when an element is referred to as being "directly coupled" or "directly connected" to another element, there are no intervening elements.

[0047] The terms used in this application are only used to describe specific exemplary embodiments and are not intended to limit the present invention. Singular expressions used herein include plural expressions unless they have clear opposite meanings in the context. In this application, it should be understood that the terms "including" and "having" are intended to specify the existence of the characteristics, quantities, steps, operations, constituent elements and parts or combinations thereof described in the specification, and do not exclude the possibility of pre-existing or adding one or more other characteristics, quantities, steps, operations, constituent elements and parts or combinations thereof.

[0048] Unless otherwise defined, all terms (including technical and scientific terms) used in this article have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0049] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0050] Figure 1 is a schematic diagram of a battery manufacturing process to which the present invention may be applied.

[0051] The battery can be manufactured by processes including electrode preparation (S10), assembly (S20), activation (S30) and packaging (S40). The battery manufactured by these processes is shipped in the form of a battery pack (or battery module) including a plurality of battery cells connected in series. The battery pack can be connected to a load through a positive terminal and a negative terminal and perform a charge / discharge operation. Depending on the requirements of the system using the battery, the battery pack can be configured to be connected in series / parallel.

[0052] More specifically, the electrode preparation process (S10) is a process for manufacturing positive and negative electrodes by mixing active electrode materials, conductive materials and binders constituting the electrodes after the raw materials are input. The assembly process (S20) is a process for manufacturing finished battery cells by assembling the positive and negative plates manufactured by the electrode process with a separator. The manufacturing order may vary depending on the battery type (cylindrical, pouch, prismatic), and the technology applied by each manufacturer may also be different. In addition, the activation process (S30) is a process for activating electrical energy and obtaining stability. The packaging process (S40) is a process for modularizing the manufactured battery cells and placing them into a battery pack.

[0053] In addition, an activation process (S30) is performed by repeatedly aging and charging / discharging. In the "aging" process, the battery is stored at a constant temperature and humidity at room temperature so that the electrolyte penetrates the negative electrode and the positive electrode. When the electrolyte is dispersed inside the battery and the movement of ions between the negative electrode and the positive electrode becomes smooth, the battery is partially charged to activate the battery cell. Here, all lithium ions move to the positive electrode and the electrolyte decomposes, forming a thin ion-conductive solid film, namely the "SEI (solid electrolyte interface)" layer, on the electrode surface. 'SEI' blocks the movement of electrons and only allows lithium ions to pass through, which is an important factor in improving the internal safety of the battery and affecting the battery performance and life.

[0054] The charged battery undergoes secondary aging at a high temperature of 40 to 70° C., which allows the SEI to become more stable and establish a uniform thickness. During this aging and charging, gas may be generated inside the battery, and the generated gas undergoes a "degassing" process to be removed.

[0055] After degassing, aging and charging are repeated several more times. Thereafter, the charging capacity is tested and defective batteries are selected. Finally, the activation process is completed by undergoing a pre-shipment discharge process in which the battery is discharged at a predetermined charging rate (usually 0.1 to 1C (C rate)) before shipping.

[0056] Here, the charging rate (C rate) is a value indicating the speed at which a battery is charged or discharged, and is also referred to as a charging / discharging rate. The unit of the charging rate is C, where C means capacity. The charging rate (C rate) is the charging / discharging current (A) divided by the rated capacity value (Ah) of the battery, and a standard value of the charging rate is 1C.

[0057] Figure 2 (a) is a diagram showing the concept of a general 1-step constant current transport pre-discharge method, Figure 2 (b) shows the flow of current used in a general 1-step constant current transport pre-discharge method, and Figure 2 (c) shows the voltage variation of multiple cells during a typical 1-step constant current pre-shipment discharge treatment.

[0058] The pre-shipment discharge method is one of the methods for matching the transport state of charge (SOC), which is the charge level of the battery cell when it is shipped. Among the methods for setting the transport SOC, the pre-shipment discharge method is a method of discharging the battery directly to the transport SOC without undergoing a full discharge. Here, the state of charge (SOC) is expressed as a percentage [%] of the battery state of charge.

[0059] Figure 2 The example of (a) shows a method of discharging before transport using a constant current (CC). Figure 2 (a) and Figure 2 (b), the battery cell is discharged at a constant rate after being fully charged to 4.xx V, and when a certain discharge amount (discharge capacity) is reached, the discharge process ends. Thereafter, the voltage (at Figure 2 In the example, 3.xx V) is used to determine the transport SOC.

[0060] Here, view Figure 2 The voltage variation of each cell during the discharge process shown in (c) shows that the voltage difference between the cells (ie, inter-battery voltage dispersion) is significant.

[0061] In other words, the pre-shipment discharge method only discharges the battery to the shipping SOC without undergoing full discharge, which can shorten the charging and discharging time but causes quality risks as the voltage dispersion between cells further increases.

[0062] Furthermore, among the methods of setting the transport SOC, the pre-transport charging method of charging the battery cells again to the transport SOC after being fully discharged has a disadvantage in that the charging time is increased because the charging is performed after the battery cells are fully discharged.

[0063] As described above, when the general pre-shipment discharge method or the pre-shipment charge method is used, there are problems of long charging and discharging time or quality risk.

[0064] Figure 3 (a) is a diagram showing the concept of a pre-transportation discharging method according to an embodiment of the present invention.

[0065] Figure 3 (b) shows the flow of current used in the pre-transport discharge method according to an embodiment of the present invention, and Figure 3 (c) shows the voltage variation of a plurality of cells during the pre-shipment discharge process according to an embodiment of the present invention.

[0066] The pre-shipping discharge method according to an embodiment of the present invention may include a discharge process across several steps. Figure 3 (a), the pre-transportation discharging method according to an embodiment of the present invention may include a first discharging stage and a second discharging stage.

[0067] Reference Figure 3 (a) and Figure 3 (b), in the pre-shipment discharge according to the embodiment of the present invention, the discharge of the battery is performed using a constant current (CC). However, the magnitude of the current applied to the first discharge stage is different from the magnitude of the current applied to the second discharge stage.

[0068] More specifically, in the first discharge stage, the battery cell is discharged at a constant rate (first current) after being fully charged, and the discharge ends when a certain amount (discharge capacity) is discharged (cut-off discharge capacity). Thereafter, in the second discharge stage, the discharge is performed using a second current having a lower value than the first current, and when the corresponding cell reaches a certain voltage (cut-off voltage), the second discharge stage ends.

[0069] Furthermore, the second discharging stage includes a plurality of specific discharging steps, and according to a preferred embodiment of the present invention, the number of the specific discharging steps included in the second discharging stage may be 3 or 5.

[0070] Here, view Figure 3 The voltage variation of each cell during the discharge process shown in (c) shows that the voltage dispersion between cells decreases significantly as the discharge progresses. In addition, at the point where the discharge is completed before transportation, the voltage dispersion between cells decreases significantly compared to the point where the discharge is completed before transportation. Figure 2 Compared with the case of the general pre-transportation discharge method shown in (c), the voltage dispersion between the cells is significantly improved.

[0071] Figure 4 is a block diagram of a pre-shipment discharge device according to an embodiment of the present invention.

[0072] Reference Figure 4 , the pre-shipment discharging device 100 according to the embodiment of the present invention may be configured to include a controller 110 , a charger-discharger 120 , and a measuring unit 130 .

[0073] The battery cell herein may be one or more battery cells undergoing a manufacturing process (particularly, an activation process). The charger-discharger 120 may perform charging and discharging operations on one or more cells under the control of the controller 110. The measuring unit 130 may measure the voltage and discharge capacity of the battery cell being charged or discharged by the charger-discharger 120, and provide the measurement data to the controller 110.

[0074] The controller 110 may control the charger-discharger 120 to control the charging and discharging operations of the battery cells. According to an embodiment of the present invention, the controller 110 may first fully charge the battery cells (e.g., to 4.xxV). The controller 110 may control the charger-discharger 120 to perform a first discharge phase based on the discharge capacity of the battery cells input from the measuring unit 130, and then perform a second discharge phase based on the measured voltage of the battery cells. A certain rest time may be given between the first discharge phase and the second discharge phase.

[0075] Here, the controller 110 may end the first discharge stage when a predetermined reference discharge capacity is reached while performing the first discharge stage. The discharge capacity may be determined according to the discharge current and the discharge time, and when the discharge is performed by an amount equal to the predetermined reference discharge capacity, the first discharge stage is completed and terminated.

[0076] In addition, when the voltage of each battery cell reaches a preset voltage while the second discharge stage is performed, the controller may terminate the second discharge stage of each battery cell.

[0077] Here, the first current value for the first discharge stage is greater than the second current value for the second discharge stage. In other words, the first discharge stage can be performed using a higher rate constant current, while the second discharge stage can be performed using a lower rate constant current.

[0078] In addition, the second discharge phase according to an embodiment of the present invention may include three or more specific discharge steps using the same or different charge / discharge rates. Therefore, the second current applied to the second discharge phase may have a value that varies according to a specific time period.

[0079] Here, the charge / discharge rate of a specific discharge step that is temporally last among the specific discharge steps may be set to a value smaller than the charge / discharge rates applied to the other specific discharge steps.

[0080] According to one embodiment, when the second discharge stage includes three specific discharge steps, the second discharge stage may include: a first specific discharge step of performing discharge using a first charge / discharge rate; a second specific discharge step of performing discharge using a second charge / discharge rate; and a third specific discharge step of performing discharge using a third charge / discharge rate.

[0081] Here, the first charge / discharge rate and the second charge / discharge rate may be set to the same value, and the third charge / discharge rate may be set to a value smaller than the first charge / discharge rate and the second charge / discharge rate. In addition, the second charge / discharge rate may be set to a value smaller than the first charge / discharge rate.

[0082] According to another embodiment, in the case of a second discharge stage having five specific discharge steps, the second discharge stage may include: a first specific discharge step of performing discharge using a first charge / discharge rate; a second specific discharge step of performing discharge using a second charge / discharge rate; a third specific discharge step of performing discharge using a third charge / discharge rate; a fourth specific discharge step of performing discharge using a fourth charge / discharge rate; and a fifth specific discharge step of performing discharge using a fifth charge / discharge rate.

[0083] Here, the first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, and the fourth charge / discharge rate are set to the same value, and the fifth charge / discharge rate may be set to a value lower than the first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, and the fourth charge / discharge rate.

[0084] According to another embodiment, the first charging / discharging rate, the second charging / discharging rate, the third charging / discharging rate, the fourth charging / discharging rate, and the fifth charging / discharging rate may be determined as different values ​​that decrease in sequence.

[0085] Here, the third charge / discharge rate may be determined based on the first charge / discharge rate and the fifth charge / discharge rate. In other words, the current corresponding to the third charge / discharge rate may be determined based on the current corresponding to the first charge / discharge rate and the current corresponding to the fifth charge / discharge rate, for example, according to the following formula 1.

[0086] [Formula 1]

[0087]

[0088] In Formula 1, I3 represents a current corresponding to a third charge / discharge rate, I1 represents a current corresponding to a first charge / discharge rate, and I5 represents a current corresponding to a fifth charge / discharge rate.

[0089] In addition, the charge / discharge rate (C rate) is a value obtained by dividing the charge / discharge current (A) by the rated capacity value (Ah) of the battery, and in this specification, it can be understood as the same meaning as the battery discharge rate. Since the rated capacity of the battery is fixed, the charge / discharge rate can correspond to the charge / discharge current.

[0090] In this specification, the controller may be a processor, any type of controller or a main control unit (MCU), etc., and may also mean a dedicated processor that executes the method according to the embodiment of the present invention.

[0091] Figure 5 An operation sequence of a method for discharging a battery before shipping according to an embodiment of the present invention is shown.

[0092] Figure 5 The battery pre-shipment discharge method shown in the figure can be executed by a battery pre-shipment discharge device or a controller in a battery pre-shipment discharge device. In this embodiment, for the convenience of explanation, the operating entity is described as a controller, but the operating entity of the battery pre-shipment discharge method according to the present invention is not limited thereto.

[0093] The controller may fully charge one or more battery cells in the activation process (S510). Thereafter, the controller may perform a first discharge phase on the one or more battery cells according to a first current value based on a predetermined discharge capacity (S520), and when the predetermined discharge capacity is reached during the first discharge phase (S521), the first discharge phase may be terminated (S522).

[0094] After executing the first discharge stage, the controller may execute a second discharge stage on one or more battery cells according to a second current value based on a predetermined voltage, the second current value varying according to a specific segmented time period (S530). As the discharge proceeds, the voltage of each battery cell gradually decreases. When the voltage (V cell ) reaches a preset voltage (V final ) (S531), the second discharge phase can be terminated for each battery cell (S532).

[0095] Here, the first current value may be greater than the second current value. In other words, the first discharge stage may be a discharge stage using a higher rate constant current, and the second discharge stage may be a discharge stage using a lower rate constant current.

[0096] In addition, the second discharge phase according to an embodiment of the present invention may include three or more specific discharge steps using the same or different charge / discharge rates. Therefore, the second current applied to the second discharge phase may have a value that varies according to a specific segmented time period.

[0097] According to an embodiment, a charge / discharge rate of a temporally last specific discharge step among three or more specific discharge steps included in the second discharge stage may be determined to be smaller than a value of charge / discharge rates applied to other specific discharge steps.

[0098] According to an embodiment, when the second discharge stage includes three specific discharge steps, the second discharge stage may include: a first specific discharge step of performing discharge using a first charge / discharge rate; a second specific discharge step of performing discharge using a second charge / discharge rate; and a third specific discharge step of performing discharge using a third charge / discharge rate.

[0099] Here, the first charge / discharge rate and the second charge / discharge rate may be set to the same value, and the third charge / discharge rate may be set to a value smaller than the first charge / discharge rate and the second charge / discharge rate. Alternatively, the second charge / discharge rate may be set to a value smaller than the first charge / discharge rate.

[0100] According to another embodiment, in the case of a second discharge stage having five specific discharge steps, the second discharge stage may include: a first specific discharge step of performing discharge using a first charge / discharge rate; a second specific discharge step of performing discharge using a second charge / discharge rate; a third specific discharge step of performing discharge using a third charge / discharge rate; a fourth specific discharge step of performing discharge using a fourth charge / discharge rate; and a fifth specific discharge step of performing discharge using a fifth charge / discharge rate.

[0101] Here, the first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, and the fourth charge / discharge rate are set to the same value, and the fifth charge / discharge rate may be set to a value lower than the first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, and the fourth charge / discharge rate.

[0102] According to another embodiment, the first charging / discharging rate, the second charging / discharging rate, the third charging / discharging rate, the fourth charging / discharging rate, and the fifth charging / discharging rate may be determined as different values ​​that decrease in sequence.

[0103] Here, the third charge / discharge rate may be determined based on the first charge / discharge rate and the fifth charge / discharge rate. In other words, the current corresponding to the third charge / discharge rate may be determined based on the current corresponding to the first charge / discharge rate and the current corresponding to the fifth charge / discharge rate. For example, the current corresponding to the third charge / discharge rate may be determined based on Formula 1 discussed previously.

[0104] Figure 6 Experimental parameters and test results for deriving an optimal pre-shipment discharge treatment according to the present invention are shown.

[0105] The inventors of the present invention conducted various experiments to determine which factors associated with the pre-shipment discharge treatment affect the discharge time and voltage standard deviation. The experiments involved a second discharge phase including three or more specific discharge steps using the same or different charge / discharge rates.

[0106] Reference Figure 6 , the main experimental factors considered in the experiment are the final C rate (charge / discharge rate) of the last specific discharge step among the multiple specific discharge steps in the second discharge stage, the intermediate C rate (charge / discharge rate) applied to the intermediate specific discharge steps, the number of specific discharge steps, and the rest time between the specific discharge steps. The final C rate can be a factor related to the voltage deviation, and the intermediate C rate, the number of specific discharge steps, and the rest time between the specific discharge steps can be identified as factors related to the discharge time.

[0107] In the experiment, for the final C rate, five different C rate levels were tested: 1.3C, 1.0C, 0.5C, 0.2C, and 0.1C. For the intermediate C rate, two levels were tested: one was an arbitrary value (1.3C, 0.8C) and the other was a value derived using the formula.

[0108] Here, the formula applied to the intermediate C rate value can be the above-discussed formula 1. In other words, the intermediate C rate value can be determined based on the C rate of the specific discharge step performed first in time within the second discharge stage and the C rate of the specific discharge step performed last in time within the second discharge stage.

[0109] In addition, experiments were conducted with the number of specific discharge steps being set to 2, 3, and 5, and the rest time being set to 5 minutes (5 min), 1 minute (1 min), and 0.

[0110] As a result of the cell test, in the case of the final C rate, the experiment shows that the lower the value, the smaller the voltage deviation, which means better. In addition, in the case of the intermediate C rate, the experiment shows that the value determined according to the C rate of the specific discharge step performed first in time within the second discharge stage and the C rate of the specific discharge step performed last in time within the second discharge stage is conducive to shortening the discharge time.

[0111] In addition, the greater the number of specific discharge steps, the more advantageous it is in terms of discharge time. In addition, the lower the rest time, the more advantageous it is in terms of shortening the discharge time.

[0112] Figure 7 Test results of several experimental examples according to different experimental parameters for deriving an optimal pre-shipment discharge treatment according to the present invention are shown.

[0113] Figure 7 Indicates the results of the test for deriving the discharge time and voltage standard deviation values ​​for each experimental example in order to determine the Figure 6 The performance of various experimental examples (numbers 1 to 12) of the desired combinations of experimental factors derived from the experiments.

[0114] In the experimental examples, three or five specific discharge steps were used, for the final C rate, a low value of 0.1 to 0.5 was used, and for the intermediate C rate, a value derived by a formula according to Equation 1 or an arbitrary value of 1.3C was used.

[0115] The target discharge time is set to less than 70 minutes, the target voltage standard deviation value is set to less than 1.0, and candidates satisfying these target conditions are selected first.

[0116] As a result of the test, Figure 7Among the experimental examples shown in , more desirable results were obtained in the experimental examples having 5 specific discharge steps. More specifically, among them, the experimental example of case 1 in which the charge / discharge rates (corresponding to the discharge current) of the specific discharge steps 1 to 5 were 1.3 / 1.3 / 1.3 / 1.3 / 0.5 and the experimental example of case 2 in which the charge / discharge rates (corresponding to the discharge current) were 1.3 / 0.7 / 0.4 / 0.2 / 0.1 were shown to be the most desirable combinations.

[0117] Case 1 is more favorable than Case 2 in terms of average discharge time, and Case 2 is more favorable than Case 1 in terms of average voltage deviation.

[0118] pass Figure 6 and Figure 7 Tests have shown that it is desirable to set the charge / discharge rate of the temporally last specific discharge step among the three or more specific discharge steps included in the second discharge stage to a value smaller than the values ​​of the remaining specific discharge steps before the last specific discharge step.

[0119] In addition, in the case where the second discharge stage includes five specific discharge steps, in terms of discharge time and voltage standard deviation, the desired results can be obtained from two cases. One case is that the first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, and the fourth charge / discharge rate are set to the same value, and the fifth charge / discharge rate is set to a value smaller than the first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, and the fourth charge / discharge rate. The other case is that the first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, the fourth charge / discharge rate, and the fifth charge / discharge rate are set to different values ​​that decrease in sequence.

[0120] Figure 8 The verification results of the optimal pre-transportation discharge method as a preferred embodiment according to the present invention are shown.

[0121] Based on Figure 7 The optimal discharge parameter combination derived from the experimental example in the paper is derived using the statistical process optimization solution as follows Figure 8 The two best examples are shown in .

[0122] The average voltage deviation and the average discharge time are used as evaluation data for deriving the final two best examples. For the candidate solution (the candidate solution includes 5 specific discharge steps, the specified final C rate and the intermediate C rate value), the average voltage deviation standard value and the average discharge time standard value are calculated independently, and the final best example is derived by comprehensively considering the average voltage deviation and the average discharge time to derive the satisfaction value.

[0123] Derived as Figure 8The final two best embodiments are shown in . Best Example Embodiment 1 has a second discharge phase process with a charging rate of 1.3 / 0.75 / 0.45 / 0.25 / 0.15, and Best Example Embodiment 2 has a second discharge phase process with a charging rate of 1.3 / 1.3 / 1.3 / 1.3 / 0.3.

[0124] The best example embodiment 1 showed an average discharge time of 72 minutes and an average voltage deviation of 0.89, thus requiring further improvement in discharge time. In addition, the best example embodiment 2 with an average discharge time of 61 minutes and an average voltage deviation of 0.94 was found to meet both the target discharge time (less than 70 minutes) and the target voltage standard deviation (less than 1.0).

[0125] A test discharge process was performed on one or more battery cells according to the best example embodiment 2, and it was identified that the voltage dispersion of the battery cells in the pallet during transportation was 0.9mV. Considering that the voltage dispersion when using a typical discharge method was 2.4V, it can be understood that an improvement in voltage dispersion of approximately 63% was achieved. In addition, the charging and discharging time was reduced by 10.4%, resulting in a saving of approximately 3.1 billion won in investment costs, and a 10% improvement in the power cost of the battery activation process.

[0126] According to the best example embodiment 1, the first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, the fourth charge / discharge rate, and the fifth charge / discharge rate may be set to different values ​​that decrease in sequence.

[0127] According to the best example embodiment 2, the first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate and the fourth charge / discharge rate are set to the same value, and the fifth charge / discharge rate can be set to a value smaller than the first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate and the fourth charge / discharge rate.

[0128] In summary, the common feature of the best example embodiment 1 and the best example embodiment 2 is that the charge / discharge rate of the specific discharge step located last in time among the specific discharge steps is smaller than the charge / discharge rates applied to other previous specific discharge steps.

[0129] Best Example Implementation 1 shows better results in terms of voltage deviation, and Best Example Implementation 2 shows better results in terms of discharge time. Therefore, in a situation where the discharge time needs to be improved more than the voltage deviation, Best Example Implementation 2 can be selected for battery activation processing. In addition, in a situation where the voltage deviation needs to be improved more than the discharge time, Best Example Implementation 1 can be selected for battery activation processing.

[0130] By using the battery pre-shipment discharge device and method of the present invention understood through the above embodiments, the voltage dispersion between battery cells can be improved, and the processing time required for pre-shipment discharge can be shortened. Therefore, the effects of reducing the investment cost of the charger and the discharger and improving the power cost of the activation process can be expected.

[0131] The operation of the method according to an embodiment of the present invention can be implemented as a computer-readable program or code on a computer-readable recording medium. The computer-readable recording medium includes all types of recording devices having data readable by a computer system stored therein. In addition, the computer-readable recording medium can be distributed in a networked computer system to store and execute a computer-readable program or code in a distributed manner.

[0132] In addition, the computer-readable recording medium may include hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, etc. The program instructions may include not only machine language codes created by a compiler, but also high-level language codes that can be executed by a computer using an interpreter.

[0133] Although some aspects of the invention have been described in the context of an apparatus, it may also be represented as a description according to a corresponding method, wherein a block or apparatus corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method step may also represent features of a corresponding block or entry or a corresponding apparatus. Some or all of the method steps may be performed by (or using) a hardware device such as (for example) a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, one or more of the most important method steps may be performed by such an apparatus.

[0134] Hereinabove, the present invention has been described with reference to exemplary embodiments thereof, but those skilled in the art will appreciate that the present invention may be variously modified and altered without departing from the spirit and scope of the invention described in the appended claims.

Claims

1. An apparatus for performing pre-transport discharge of one or more battery cells, the apparatus comprising: a charger-discharger connected to the one or more battery cells and configured to charge or discharge the one or more battery cells; a measurement unit configured to monitor each battery cell and provide relevant measurement values ​​to the controller; as well as a controller configured to control the charger-discharger to perform a first discharge phase on the one or more battery cells according to a first current value based on a predetermined discharge capacity, and to perform a second discharge phase on the one or more battery cells according to a second current value based on a predetermined voltage, the second current value varying according to a specific time period, Wherein the controller controls the charger-discharger to perform the first discharge stage and the second discharge stage before transporting the one or more battery cells.

2. The device according to claim 1, wherein: In a case where the predetermined discharge capacity is reached while performing the first discharge stage, the controller terminates the first discharge stage.

3. The device according to claim 1, wherein: In a case where the voltage of each battery cell reaches the predetermined voltage when the second discharging stage is performed, the controller terminates the second discharging stage of each battery cell.

4. The device according to claim 1, wherein: The first current value is greater than the second current value.

5. The device according to claim 1, wherein: The second discharge phase includes three or more specific discharge steps using the same or different charge and discharge rates.

6. The device according to claim 5, wherein: The charge / discharge rate of a specific discharge step located last in time among three or more specific discharge steps included in the second discharge stage is determined to have a value smaller than the charge / discharge rates applied to the remaining specific discharge steps.

7. The device according to claim 5, wherein: The second discharge stage includes: performing a first specific discharge step of discharging using a first charge / discharge rate; a second specific discharge step of performing discharge using a second charge / discharge rate; a third specific discharge step of performing discharge using a third charge / discharge rate; a fourth specific discharging step of performing discharging using a fourth charge / discharge rate; A fifth specific discharge step of discharging is performed using a fifth charge / discharge rate.

8. The device according to claim 7, wherein: The first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, and the fourth charge / discharge rate are determined to be the same value, and The fifth charge / discharge rate is determined to be smaller than the first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, and the fourth charge / discharge rate.

9. The device according to claim 7, wherein: The first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, the fourth charge / discharge rate, and the fifth charge / discharge rate are determined to be different values ​​that decrease in sequence.

10. The device according to claim 9, wherein: The third charging / discharging rate is determined according to the first charging / discharging rate and the fifth charging / discharging rate.

11. The device according to claim 1, wherein: The controller fully charges the one or more battery cells before executing the first discharge phase.

12. A method for performing pre-shipment discharge of one or more battery cells, the method comprising the steps of: performing a first discharge phase on the one or more battery cells according to a first current value based on a predetermined discharge capacity; as well as performing a second discharge phase on the one or more battery cells according to a second current value based on a predetermined voltage, the second current value varying according to a specific time period, Therein, the first discharge phase and the second discharge phase are performed before transporting the one or more battery cells.

13. The method according to claim 12, wherein: The step of performing the first discharge stage includes the following steps: when the predetermined discharge capacity is reached during the first discharge stage, terminating the first discharge stage.

14. The method according to claim 12, wherein: The step of performing the second discharge stage includes the following steps: when the voltage of each battery cell reaches the predetermined voltage during the execution of the second discharge stage, terminating the second discharge stage of each battery cell.

15. The method according to claim 12, wherein: The first current value is greater than the second current value.

16. The method according to claim 12, wherein: The second discharge phase includes three or more specific discharge steps using the same or different charge and discharge rates.

17. The method according to claim 16, wherein: The charge / discharge rate of a specific discharge step located last in time among three or more specific discharge steps included in the second discharge stage is determined to have a value smaller than the charge / discharge rates applied to the remaining specific discharge steps.

18. The method according to claim 16, wherein: The second discharge stage comprises the following steps: performing a first specific discharge step of discharging using a first charge / discharge rate; a second specific discharge step of performing discharge using a second charge / discharge rate; a third specific discharge step of performing discharge using a third charge / discharge rate; a fourth specific discharging step of performing discharging using a fourth charge / discharge rate; A fifth specific discharge step of discharging is performed using a fifth charge / discharge rate.

19. The method according to claim 18, wherein: The first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, and the fourth charge / discharge rate are determined to be the same value, and The fifth charge / discharge rate is determined to be smaller than the first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, and the fourth charge / discharge rate.

20. The method according to claim 18, wherein: The first charge / discharge rate, the second charge / discharge rate, the third charge / discharge rate, the fourth charge / discharge rate, and the fifth charge / discharge rate are determined to be different values ​​that decrease in sequence.

21. The method according to claim 20, wherein: The third charging / discharging rate is determined according to the first charging / discharging rate and the fifth charging / discharging rate.

22. The method according to claim 12, further comprising the steps of: The one or more battery cells are fully charged before performing the first discharge phase.

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