Battery charging method and apparatus

Abstract

A battery charging method according to one embodiment of the present invention is a method of charging a battery by dividing the charging interval into a plurality of charging intervals, and includes a first discharge step of applying a first discharge pulse between the n-1 (where n is a natural number of 2 or more)th charging interval and the nth charging interval, and a second discharge step of applying a second discharge pulse between the nth charging interval and the n+1th charging interval. Here, the discharge rate of the second discharge pulse is configured to be lower than the discharge rate of the first discharge pulse.

Description

Technical Field

[0001] This application claims priority based on Korean Patent Application No. 10-2023-0098508 filed on July 27, 2023, and all the content disclosed in the specification and drawings of that application is incorporated herein by reference.

[0002] The present invention relates to a battery charging method and apparatus, and more specifically, to a battery charging method and apparatus capable of maximizing the charging efficiency of a battery by applying a discharge pulse during the charging process and varying the environment in which the discharge pulse is applied.

Background Art

[0003] As the demand for portable electronic products such as laptops, video cameras, and mobile phones that use electricity as a driving source has rapidly increased, and as mobile robots, electric bicycles, electric carts, and electric vehicles have become generally commercialized, research on high-performance secondary batteries that can be repeatedly charged and discharged has been actively conducted.

[0004] Currently, commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium secondary batteries, etc. Among them, lithium secondary batteries have almost no memory effect compared to nickel-based secondary batteries, so they can be freely charged and discharged, have the advantage of a very low self-discharge rate, and also have the characteristics of high energy density and high operating voltage. Therefore, they are being more intensively studied than other types of secondary batteries and are being more extensively applied to actual products.

[0005] In recent years, secondary batteries are widely used not only in small devices such as portable electronic devices but also in medium and large-sized devices such as electric vehicles and energy storage systems (ESS).

[0006] In this case, battery modules, in which numerous electrically connected secondary batteries are housed together inside a module case, are primarily used. Furthermore, when higher power or capacity is required, battery packs, in which numerous battery modules are electrically connected, are used.

[0007] In secondary battery cells, cell assemblies, battery modules, or battery packs (hereinafter collectively referred to as "batteries"), power efficiency and safety are important factors. Therefore, research is actively being conducted on battery management systems (BMS) that monitor the electrical characteristics of batteries and perform feedback control such as charging and discharging using the monitoring results.

[0008] On the other hand, in order to more effectively reflect user needs and improve various aspects of the environment through increased battery capacity, various studies are being conducted on battery charging, such as rapid charging.

[0009] Battery charging methods include not only the constant current-constant voltage (CC) method, but also pulse charging, boost charging, and multi-step CC charging.

[0010] When charging a battery in a high-current environment to shorten the charging time, lithium cations (Li) supplied to the negative electrode + However, if the lithium cannot be absorbed quickly, it may accumulate on the negative electrode and be deposited as lithium metal, a phenomenon known as lithium plating (Li-plating).

[0011] Such phenomena can cause side reactions with the electrolyte and alter the battery's kinetic balance, leading to a decrease in battery performance, reduced capacity, and ultimately, battery degradation or a shortened lifespan.

[0012] Furthermore, if such a phenomenon occurs, the formation of non-uniform lithium crystals (lithium dendrites) increases the likelihood of short circuits, which could lead to fatal safety problems such as fires and explosions. [Overview of the project] [Problems that the invention aims to solve]

[0013] The present invention was devised to solve the above-mentioned problems, and aims to provide a battery charging method and apparatus that can fundamentally eliminate problems caused by lithium deposition and further optimize charging efficiency, such as rapid charging, by applying a discharge mode that applies discharge pulses between charging sections divided into multiple sections and making the discharge environment of each discharge mode different.

[0014] The technical problems that this invention aims to solve are not limited to those described above, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described later. [Means for solving the problem]

[0015] A battery charging method according to one aspect of the present invention is a method of charging a battery by dividing the charging interval into a plurality of charging intervals, comprising: a first discharge step of applying a first discharge pulse between the n-1 (where n is a natural number of 2 or more)th charging interval and the nth charging interval; and a second discharge step of applying a second discharge pulse between the nth charging interval and the n+1th charging interval.

[0016] The discharge rate of the second discharge pulse may be configured to be less than the discharge rate of the first discharge pulse.

[0017] The application time of the second discharge pulse may be configured to be equal to or greater than the application time of the first discharge pulse.

[0018] The discharge rate and application time of the first discharge pulse or the second discharge pulse may be set so that the discharge amount of the second discharge stage is less than or equal to the discharge amount of the first discharge stage.

[0019] The charge level of the nth charging interval may be set lower than the charge level of the (n-1)th charging interval.

[0020] The charging environment of the multiple charging intervals may be configured to be variably determined according to the State of Charge (SOC) value estimated based on the change in the characteristic data of the battery due to charging.

[0021] The charging environment may be one or more of the lengths of each of the multiple charging sections and the charge levels of each of the multiple charging sections.

[0022] A battery charging device according to another aspect of the present invention includes a charging unit configured to charge a battery, a discharging unit configured to discharge the battery, and a control unit configured to control the charging unit so that the battery is charged in a plurality of charging intervals, and to control the discharging unit so that a first discharge pulse is applied between the n-1 (where n is a natural number of 2 or more)th charging interval and the nth charging interval, and a second discharge pulse is applied between the nth charging interval and the n+1th charging interval.

[0023] The control unit may be configured to control the discharge unit such that the discharge rate of the second discharge pulse is less than the discharge rate of the first discharge pulse.

[0024] The control unit may be configured to control the discharge unit such that the application time of the second discharge pulse is equal to or greater than the application time of the first discharge pulse.

[0025] The control unit may be configured to control the discharge rate and the application time of the first discharge pulse or the second discharge pulse so that the discharge amount of the second discharge pulse is less than or equal to the discharge amount of the first discharge pulse.

[0026] The control unit may be configured to control the charging unit so that the charging environments of the plurality of charging intervals are variably set using a preset target SOC.

[0027] The target SOC may be estimated as the SOC value at which lithium is deposited based on the change in the characteristic data of the battery due to charging.

Advantages of the Invention

[0028] According to one aspect of the present invention, by applying a discharging process in which charging is performed in a plurality of intervals and a discharging pulse is applied during charging in each interval, not only can lithium precipitation be minimized, but also the precipitated lithium can be more effectively removed.

[0029] Further, according to one aspect of the present invention, by varying and applying the discharging environment, specifically the application time of the discharging pulse and the discharging rate of the discharging pulse, in a series of discharging processes performed in time series, not only can the charging efficiency such as shortening of the charging time be further improved, but also the driving performance or durability of the battery can be further improved by delaying or blunting the deterioration process of the battery.

[0030] Furthermore, according to one aspect of the present invention, by organically combining the electrical characteristic data of the battery and variably setting the charging environment of each charging interval performed in a plurality of intervals, a charging environment optimized for the state of the battery that changes over time can be realized.

[0031] The drawings attached to this specification serve to make the technical idea of the present invention easier to understand together with the detailed description of the invention described later, and the present invention is not to be construed as being limited only to the matters described in the drawings. [Brief explanation of the drawing]

[0032] [Figure 1] This is a block diagram showing the detailed configuration of a battery charging device according to one embodiment of the present invention. [Figure 2] This is a block diagram showing the detailed configuration of the data processing unit. [Figure 3] This is a flowchart illustrating the process according to one embodiment of the present invention. [Figure 4] This is a flowchart illustrating the process steps according to another embodiment of the present invention. [Figure 5] This figure illustrates one embodiment of the discharge rate of the discharge pulse for each discharge section. [Figure 6] This figure illustrates one embodiment of the application time of discharge pulses for each discharge section. [Figure 7] This diagram illustrates the time-series characteristics of the discharge environment for each discharge interval, based on the overall charging process. [Figure 8] This diagram illustrates the time-series characteristics of the discharge environment for each discharge interval, based on the overall charging process. [Figure 9] This diagram illustrates the process of determining the State of Charge (SOC) at which lithium is deposited during charging. [Figure 10] This figure shows the performance results of a battery according to an embodiment of the present invention, based on the discharge capacity retention rate. [Modes for carrying out the invention]

[0033] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Prior to this, terms and words used herein and in the claims shall not be interpreted in their general and dictionary sense, but in accordance with the principle that inventors may appropriately define the concepts of terms in order to best describe their invention, and shall be interpreted in the sense and concepts corresponding to the technical idea of ​​the present invention.

[0034] Therefore, the embodiments described herein and the configurations shown in the drawings represent only one of the most preferred embodiments of the present invention and do not represent the entire technical concept of the invention. It should be understood that there are various equivalents and modifications that can substitute for them at the time of filing this application.

[0035] Furthermore, in describing the present invention, if it is determined that a specific description of a related known configuration or function would obscure the gist of the present invention, such detailed description will be omitted.

[0036] When a part of the specification "includes" a certain component, unless otherwise specified, this does not exclude other components, but rather means that it may include other components.

[0037] Furthermore, terms such as "processor" as used in the specification refer to a unit that processes at least one function or operation, and can be implemented in hardware, software, or a combination of hardware and software.

[0038] Furthermore, when a part of the specification is described as being "connected" to another part, this includes not only "direct connections" but also "indirect connections" mediated by other elements.

[0039] Figure 1 is a block diagram showing the detailed configuration of a battery charging device 100 according to one embodiment of the present invention.

[0040] As shown in Figure 1, the battery charging device 100 of the present invention may include an interface unit 110, a charging unit 120, a discharge unit 130, a control unit 140, and a detection unit 160.

[0041] Prior to a detailed description of the present invention, the battery charging device 100 of the present invention can be realized through the application of various combinations of electronic elements and components such as storage means, arithmetic processing means, and input / output means (ASIC (Application-Specific Integrated Circuit), chipset, logic circuit, register, communication modem, MCU (Micro Controller Unit), etc.).

[0042] Therefore, each component of the battery charging device 100 shown in Figure 1 is understood to be a functionally or logically distinct component, rather than a physically distinct component.

[0043] In other words, each component shown in the figure corresponds to a logical configuration for effectively explaining the technical idea of ​​the present invention. Therefore, even if each component is integrated or separated, as long as the function performed by the logical configuration of the present invention is realized, it is interpreted as being within the scope of the present invention. Furthermore, if the components perform the same or similar functions, regardless of whether their names match, they are interpreted as being within the scope of the present invention. The same applies to the data calculation unit 150 shown in Figure 2.

[0044] Furthermore, since the battery charging method according to one embodiment of the present invention can be implemented as a collection of processes or algorithms related to data processing, handling, control, and calculation, it can be implemented not only by the combination of logical configurations shown in Figure 1, but also in the form of software installed and driven by a computer or similar terminal or module.

[0045] For example, a battery charging method can be applied to a battery management system (BMS). When connected to a charging device, the BMS can rapidly charge the battery by controlling the charging and discharging of the battery according to a battery charging method according to one embodiment of the present invention.

[0046] As another example, a battery charging method may be applied to a charging device. The charging device is capable of rapidly charging a battery according to a battery charging method according to one embodiment of the present invention.

[0047] The charging unit 120 of the present invention is electrically connected to the battery 50 and performs a charging process targeting the battery 50. Depending on the embodiment, as shown in Figure 1, the charging unit 120 of the present invention may be electrically connected to the battery 50 via an interface unit 110 that is linked to physical means such as a jack or socket.

[0048] Since various forms such as secondary battery cells, cell banks, cell assemblies, cell modules, and battery packs can be the target of charging, in the following explanation, "battery 50" may refer to a general entity including cells, cell banks, cell assemblies, cell modules, and battery packs.

[0049] The discharge unit 130 of the present invention is configured to discharge a battery 50, and, similar to the charging unit 120 described above, may be electrically connected to the battery 50 via an interface unit 110, or, depending on the embodiment, may be electrically connected to the battery 50 via an interface unit independent of the charging unit 120.

[0050] The control unit 140 of the present invention is configured to communicate with the charging unit 120 and the discharging unit 130, and to control the charging process performed by the charging unit 120 and the discharging process performed by the discharging unit 130.

[0051] A battery charging device 100 according to one embodiment of the present invention does not perform a continuous charging process from the start to the end of charging, but rather divides the charging process into k intervals (where k is a natural number of 2 or more) to charge the battery 50 (hereinafter referred to as the "multi-step charge mode").

[0052] A battery charging device 100 according to one embodiment of the present invention is configured to charge a battery by dividing the charging period into a plurality of charging periods, to apply a first discharge pulse between the (n-1)th (where n is a natural number of 2 or more)th charging period and the nth charging period, and to apply a second discharge pulse between the nth charging period and the (n+1)th charging period.

[0053] However, depending on the embodiment, the discharge pulse does not necessarily have to be applied between each charging interval. For example, if the first discharge pulse is applied between the (n-1)th charging interval and the nth charging interval, the second discharge pulse may not be applied between the nth charging interval and the (n+1)th charging interval. Then, the third discharge pulse may be applied between the (n+1)th charging interval and the (n+2)th charging interval.

[0054] First, the overall charging process performed by one embodiment of the present invention will be described, and the specific details of each discharge mode or discharge process performed by applying a discharge pulse will be described later.

[0055] Figure 3 is a flowchart illustrating the charging process according to the present invention, showing the charging process based on one embodiment in which the charging section is divided into three parts.

[0056] When a physical connection is made between the battery 50 and the charging unit 120 (or interface unit 110), and charging is initiated through methods such as inputting an electrical signal, selecting a button or interface related to starting charging (S300), the control unit 140 of the present invention controls the charging unit 120 so that charging is driven according to the charging environment of the first charging section (S310).

[0057] The charging environment refers to the time during which charging takes place, that is, one or more of the length of the charging section, the magnitude of the charging current, and the charge level. Preferably, the charging environment is configured to be variably set to reflect the current state of the battery 50, as described later. In the case of a multi-stage charging system, it is preferable that the magnitude of the charging current or the charge level decreases as the charging progresses to subsequent charging sections.

[0058] If the State of Charge (SOC) of the battery 50 reaches the first target SOC through the charging of the first charging section (hereinafter referred to as "first charging") (S320), the first charging is terminated. Depending on the embodiment, the termination condition for the first charging may be determined not only by whether or not the SOC of the battery 50 has reached the first target SOC as described above, but also by whether or not the charging voltage of the battery 50 has reached the first critical voltage.

[0059] Subsequently, the control unit 140 of the present invention controls the discharge unit 130 so that the battery 50, which has completed its first charge, is driven to discharge according to the discharge environment of the first discharge mode (S330). The discharge environment refers to one or more of the following: the magnitude of the discharge pulse, the discharge rate of the discharge pulse, and the application time of the discharge pulse.

[0060] When the discharge of the first discharge mode (hereinafter referred to as "first discharge") satisfies a preset first condition (such as discharge time or the current SOC of the battery 50) (S340), the control unit 140 of the present invention controls the discharge unit 130 to terminate the first discharge and further controls the charging unit 120 to start charging in the second charging section (second charge) (S350).

[0061] As described above, the second charge is also driven according to the charging environment (one or more of the following: length of the charging section, magnitude of the charging current, and charge level) that is specifically set for the second charging section.

[0062] If the State of Charge (SOC) of the battery 50 reaches the second target SOC through the second charge (S360), the control unit 140 of the present invention controls the charging unit 120 to terminate the second charge and controls the discharge unit 130 so that discharge is driven according to the discharge environment of the second discharge mode (S370).

[0063] When the discharge of the second discharge mode (hereinafter referred to as "second discharge") satisfies a preset second condition (such as the discharge time or the current SOC of the battery 50) (S380), the control unit 140 of the present invention controls the discharge unit 130 to terminate the second discharge and controls the charging unit 120 to start the charging of the final third charging section (third charge) (S390).

[0064] When the State of Charge (SOC) of the battery 50 reaches the final target SOC (S395) through the third charging method, the entire charging process of the present invention is terminated.

[0065] Figure 3 shows a process for one embodiment of the present invention, and it goes without saying that charging can be performed by dividing it into even more charging sections depending on the embodiment. When the charging is divided into even more charging sections in this way, it may be configured so that discharge is performed by applying discharge pulses in at least two of the charging sections, and a predetermined rest period may be applied between charging sections to eliminate lithium deposition in the space between which the discharge process is not applied.

[0066] Figure 4 is a flowchart illustrating the process according to another embodiment of the present invention.

[0067] Referring to Figure 3, the above-described embodiment of the present invention corresponds to an embodiment in which charging is performed on a battery 50 that is completely discharged or equivalent, or on a battery 50 that corresponds to a lower SOC.

[0068] The embodiment shown in Figure 4 is an embodiment in which the current SOC of the battery 50 to be charged is determined, and the charging section corresponding to the current SOC of the battery 50 is set as the starting section for charging from among the charging sections which are divided into multiple sections, and charging is performed.

[0069] As described above, when a signal related to the start of charging is input (S400), the detection unit 160 of the present invention determines the current state of charge (SOC) of the battery 50 using the electrical characteristic values ​​(voltage, etc.) of the battery 50 (S410), and outputs the result data to the control unit 140 of the present invention.

[0070] When data on the current state of charge (SOC) of the battery 50 is input, the control unit 140 of the present invention selects a charging section from a plurality of preset charging sections that corresponds to the current SOC (S420), and controls the charging unit 120 so that charging begins in the charging environment (charge rate, magnitude of charging current, etc.) of the selected charging section (S430).

[0071] After the State of Charge (SOC) of battery 50 reaches the target SOC for the relevant charging section (S440), if the current charging section is not the last of several pre-set charging sections (S450), the stepwise charging and discharging processes between charging sections, as explained with reference to Figure 3, are performed cyclically (S460).

[0072] Figure 5 illustrates one embodiment of the discharge rate of the discharge pulse for each discharge section, and Figure 6 illustrates one embodiment of the application time of the discharge pulse for each discharge section.

[0073] Figure 5 shows an embodiment in which four discharge processes are applied to a battery 50, based on the State of Charge (SOC) that increases with charging.

[0074] If no discharge process is applied after the last charging interval, this embodiment may correspond to an embodiment in which the battery 50 is charged in five or more charging intervals. If all discharge processes are applied between the current charging interval and the next charging interval, based on the chronological order of charging, the first discharge is applied between the first and second charges, the second discharge is applied between the second and third charges, the third discharge is applied between the third and fourth charges, and finally the fourth discharge is applied between the fourth and fifth charges.

[0075] As shown in Figure 5, it is preferable that the discharge rate (C rate) of the first discharge pulse applied in the first discharge (discharge of the first discharge mode) be set to the highest possible value, and that the discharge rate of the second discharge pulse applied in the second discharge following the first discharge be configured to be smaller than the discharge rate of the first discharge pulse. Furthermore, it is preferable that, based on the time series order, the discharge rate of the corresponding discharge mode gradually decreases as you move to the third discharge, fourth discharge, and so on.

[0076] Based on the embodiment shown in Figure 5, b (discharge rate of the second discharge) is smaller than a (discharge rate of the first discharge) and larger than c (discharge rate of the third discharge). Furthermore, it is preferable that d (discharge rate of the fourth discharge) is set to be smaller than c.

[0077] Specifically, it is preferable that the discharge rate of the first discharge pulse applied between the n-1 (where n is a natural number greater than or equal to 2)-th charging interval and the n-th charging interval is greater than the discharge rate of the second discharge pulse applied between the n-th charging interval and the n+1-th charging interval. In other words, it is preferable that the discharge rate of the second discharge pulse is set to be less than the discharge rate of the first discharge pulse.

[0078] When configured in this way, the removal of lithium deposited by charging in the relevant charging section can be further accelerated, and the degradation of the battery 50's performance can be more effectively suppressed.

[0079] Depending on the embodiment, as shown in Figure 6, it is preferable that the discharge time of a subsequent discharge mode (the time during which a discharge pulse is applied (the time during which discharge occurs)) is configured to be equal to or greater than the discharge time of the previous discharge mode, based on the chronological order. For example, the discharge time of the current discharge mode may be the same as or greater than the discharge time of the previous discharge mode.

[0080] Based on the embodiment shown in Figure 6, T2 (the time during which the second discharge occurs) is longer than T1 (the time during which the first discharge occurs) and shorter than T3 (the time during which the third discharge occurs). Furthermore, it is preferable that T4 (the time during which the fourth discharge occurs) is longer than T3. However, although Figure 6 shows an embodiment in which the discharge time of the nth discharge exceeds the discharge time of the (n-1)th discharge, as described above, an embodiment in which the discharge time of the nth discharge is the same as the discharge time of the (n-1)th discharge can also be applied.

[0081] Specifically, it is preferable that the application time of the first discharge pulse applied between the n-1 (where n is a natural number greater than or equal to 2)th charging interval and the nth charging interval be configured to be less than or equal to the application time of the second discharge pulse applied between the nth charging interval and the n+1th charging interval. In other words, it is preferable that the application time of the second discharge pulse be configured to be greater than or equal to the application time of the first discharge pulse.

[0082] When configured in this way, the removal of lithium deposited by charging in the relevant charging section can be more stably induced, improving the charging efficiency of the battery 50, and effectively suppressing performance degradation of the battery 50.

[0083] Figures 7 and 8 illustrate the time-series characteristics of the discharge environment for each discharge interval, relative to the overall charging process.

[0084] In the embodiments shown in Figures 7 and 8, considering the charging direction, it is preferable that the magnitude of the discharge pulse (discharge rate) in the discharge mode decreases as the discharge mode progresses to subsequent discharge modes.

[0085] Furthermore, in the embodiments shown in Figures 7 and 8, considering the charging direction, it is preferable that the application time of the discharge pulse in the discharge mode is configured to become longer or remain the same as the subsequent discharge mode. More preferably, it is preferable that the application time of the discharge pulse becomes longer as the subsequent discharge mode progresses.

[0086] Depending on the embodiment, it is preferable to set the discharge rate of the discharge pulse and the application time of the corresponding discharge pulse so that the discharge amount of each discharge mode decreases or remains the same as the subsequent discharge modes.

[0087] As an example, based on the embodiment shown in Figure 7, the discharge amount of the first discharge can be defined by the multiplication of the discharge rate (A) of the discharge pulse and the application time (T1) of the discharge pulse. Therefore, the discharge environment (discharge rate of the discharge pulse and application time of the discharge pulse) for each discharge mode can be configured to be set under the condition that the following equation 1 is satisfied.

[0088] [Formula 1] A×T1≧…≧F×T P-1 ≧G×T P

[0089] From this perspective, the control unit 140 of the present invention may be configured to control the discharge rate and application time of the first discharge pulse or the second discharge pulse so that the discharge amount of the second discharge pulse is less than or equal to the discharge amount of the first discharge pulse.

[0090] As described above, the first discharge pulse refers to the discharge pulse applied between the n-1 (where n is a natural number greater than or equal to 2)th charging interval and the nth charging interval, and the second discharge pulse refers to the discharge pulse applied between the nth charging interval and the n+1th charging interval.

[0091] The control unit may be configured to control the charging unit so that the charging environment for multiple charging sections is variably set using a preset target SOC.

[0092] Here, the charging environment of the charging section refers to one or more of the following: the length of the charging section (the time during which charging takes place), the magnitude of the charging current, and the charge level.

[0093] Specifically, the target SOC can be estimated as the SOC value at which lithium is deposited, based on the changes in battery characteristic data due to charging.

[0094] Figure 9 is a profile showing the relationship between the State of Charge (SOC) and voltage of the battery 50 during charging. Specifically, the embodiment shown in Figure 9 is a charging profile that shows the correspondence between the SOC and voltage of the battery when the battery is charged using a multi-stage charging method according to one embodiment of the present invention.

[0095] More specifically, an embodiment of the present invention will be described in detail, which sets multiple charging intervals, etc., by organically reflecting the current state of the battery 50 (degree of degradation, SOH (State of Health), etc.).

[0096] Figure 2 is a block diagram showing the detailed configuration of the data processing unit 150.

[0097] Referring to Figure 2, the data calculation unit 150 includes a data generation unit 151, an estimation unit 153, and an output unit 155, and is configured to estimate the SOC value of lithium deposited during the charging process and output the corresponding data to the control unit 140 of the present invention.

[0098] Once the target SOC, estimated as the SOC value at which lithium is deposited, is input to the control unit 140, the control unit 140 can variably set the charging environment for multiple charging sections based on the target SOC. The control unit 140 can then control the charging unit 120 and the discharging unit 130 based on the target SOC.

[0099] A data generation unit 151, which is part of the data calculation unit 150, is configured to generate characteristic data of the battery 50 after charging. This characteristic data may include the voltage of the battery 50, the rate of change of the voltage, the rate of increase of the voltage (gradient value), and the rate of change of the rate of increase of the voltage (rate of change of the gradient value).

[0100] The target battery 50 from which characteristic data is generated may be a non-degraded battery (for example, a BOL (Beginning of Life) battery) with specifications equivalent to the battery 50 currently being charged, as well as multiple batteries classified by State of Health (SOH).

[0101] Once characteristic data is generated, the estimation unit 153 of the present invention estimates the target SOC (A, Figure 9) on which lithium is deposited based on the characteristic data or changes in the characteristic data, and the output unit 155 of the data calculation unit 150 outputs the target SOC to the control unit 140. Of course, there may be multiple target SOCs (A), as shown in Figure 9.

[0102] Once a target SOC is input in this manner, the control unit 140 variably sets the points to which the charging environment and discharge mode for multiple charging sections are applied using multiple target SOCs. Preferably, not only the target SOC, but also the setting data for the charging environment determined by the target SOC, etc., are stored in a database and utilized as data associated with the degradation level of the battery 50, etc.

[0103] In the embodiment shown in Figure 1, a data processing unit 150 is included in the battery charging device 100 according to one embodiment of the present invention. However, the data processing unit 150 may be configured as a separate device located outside the battery charging device 100. In this case, the data processing unit 150 is connected to the control unit 140 via wired and / or wireless communication and can transmit information regarding the target SOC to the control unit 140. For example, the data processing unit 150 may be a cloud computing device that estimates the target SOC for each battery, taking into account the degree of battery degradation, and databases the estimated target SOCs.

[0104] Figure 10 shows the performance results of a battery according to an embodiment of the present invention, based on the discharge capacity retention rate. As is well known, batteries have a behavioral characteristic in which their discharge capacity retention rate decreases as use (charging and discharging) continues or is repeated.

[0105] Figure 10, section 200, is a graph of the battery's behavioral characteristics when only the common condition of charging at a charge rate (magnitude of charging current) that decreases as the battery progresses to subsequent charging sections is applied. Figure 10, section 300, is a graph of the battery's behavioral characteristics when discharge pulses are applied between charging sections, with the common condition described above, plus the condition that discharge pulses with the same discharge rate are applied for the same duration to all discharge modes. Figure 10, section 400, is a graph of the battery's behavioral characteristics when discharge pulses are applied between charging sections, with the common condition described above, plus the condition that the discharge rate decreases and the duration of discharge pulse application increases as the battery progresses to subsequent discharge modes.

[0106] As shown in Figure 10, in the case of 400 to which the process according to a preferred embodiment of the present invention is applied, it can be confirmed that the durability and performance retention rate of the battery 50 itself are clearly improved, as the degradation of performance is significantly delayed or slowed compared to 200 and 300.

[0107] As described above, the present invention has been explained with limited embodiments and drawings, but it goes without saying that the present invention is not limited thereto, and that various modifications and variations are possible within the equivalent scope of the technical idea and claims of the present invention by persons with ordinary skill in the art to which the present invention pertains.

[0108] The drawings and other illustrations accompanying the present invention, which describe the present invention and illustrate embodiments, may be shown in a somewhat exaggerated form to emphasize the technical content of the present invention. However, considering the above content and the illustrated matters, it is obvious to a person skilled in the art that various modified forms can be applied.

[0109] Furthermore, in the description of the present invention, expressions such as first, second, upper, lower, or top and bottom are merely instrumental conceptual terms used to relatively distinguish each component (element) from one another, and are not terms used to indicate specific procedures, priorities, etc., or to physically distinguish each component (element) by absolute criteria. [Explanation of symbols]

[0110] 100: Battery charger 110: Interface section 120:Charging part 130:Discharge part 140: Control Unit 150: Data Processing Unit 151: Data Generation Unit 153: Estimation part 155: Output section 160: Detection unit

Claims

1. A battery charging method that divides the charging section into multiple charging sections to charge the battery, A first discharge step in which a first discharge pulse is applied between the n-1 (where n is a natural number greater than or equal to 2)th charging interval and the nth charging interval, The second discharge step includes applying a second discharge pulse between the nth charging interval and the (n+1)th charging interval, A battery charging method wherein the discharge rate of the second discharge pulse is less than the discharge rate of the first discharge pulse.

2. The battery charging method according to claim 1, wherein the application time of the second discharge pulse is equal to or greater than the application time of the first discharge pulse.

3. The battery charging method according to claim 2, wherein the discharge rate and application time of the first discharge pulse or the second discharge pulse are set so that the discharge amount of the second discharge stage is less than or equal to the discharge amount of the first discharge stage.

4. The battery charging method according to claim 1, wherein the charge rate of the nth charging interval is lower than the charge rate of the (n-1)th charging interval.

5. The battery charging method according to claim 1, wherein the charging environment of the plurality of charging sections is configured to be variably determined according to the SOC value estimated based on the change in the characteristic data of the battery due to charging.

6. The battery charging method according to claim 5, wherein the charging environment is one or more of the lengths of each of the plurality of charging sections and the charge levels of each of the plurality of charging sections.

7. A charging unit configured to charge the battery, A discharge unit configured to discharge the aforementioned battery, The system includes a control unit configured to control the charging unit so that the battery is charged in multiple charging intervals, and to control the discharge unit so that a first discharge pulse is applied between the n-1 (where n is a natural number of 2 or more)th charging interval and the nth charging interval, and a second discharge pulse is applied between the nth charging interval and the n+1th charging interval, The control unit is configured to control the discharge unit so that the discharge rate of the second discharge pulse is less than the discharge rate of the first discharge pulse, in a battery charging device.

8. The battery charging device according to claim 7, wherein the control unit is configured to control the discharge unit such that the application time of the second discharge pulse is equal to or greater than the application time of the first discharge pulse.

9. The battery charging device according to claim 8, wherein the control unit is configured to control the discharge rate and application time of the first discharge pulse or the second discharge pulse so that the discharge amount of the second discharge pulse is less than or equal to the discharge amount of the first discharge pulse.

10. The control unit is configured to control the charging unit so that the charging environment of the plurality of charging sections is variably set using a preset target SOC. The battery charging device according to claim 7, wherein the target SOC is estimated as the SOC value at which lithium is deposited, based on the change in the characteristic data of the battery due to charging.

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