Method for improving the lifespan of a battery

Abstract

Method for increasing the life of a battery. The present disclosure relates to a method performed by a battery charger configured to charge a vehicle battery, the method comprising: starting to charge the battery in a bulk charging mode at a first time point (t_Bulk_Start), determining that charging of the battery in the bulk charging mode is complete at a second time point (t_Bulk_End) after the first time point (t_Bulk_Start), estimating the state of charge of the battery at the first time point (t_Bulk_Start) when starting to charge the battery in the bulk charging mode at the second time point (t_Bulk_End), and starting to charge the battery in a subsequent charging mode using the estimated state of charge (SoC_Bulk_Start), wherein the subsequent charging mode is selected from an absorption charging mode and a floating charging mode.

Description

[0001] The present invention relates to a method performed by a battery charger configured to charge a battery of a vehicle. In particular, the battery charger is configured to charge a starter battery of the vehicle. Background Art

[0002] Vehicles using combustion drives typically include a starter battery for cranking and starting the engine, typically a lead-acid based starter battery. The vehicle may further include one or more service batteries to support various accessories for providing services.

[0003] Many multi-purpose vehicles (such as fire trucks, buses, ambulances, etc.) are equipped with such additional accessories that provide a constant load to the starter and / or service batteries. Such accessories can be, for example, on-vehicle chargers for portable equipment, interior lighting, or climate control devices. Due to this constant load, whenever the vehicle is parked at its home location (usually in a garage or a fire station), charging of the battery typically begins.

[0004] When using an intelligent charger, starting to charge the battery typically involves restarting a series of charging modes, such as a bulk charging mode, an absorption charging mode, and a float charging mode.

[0005] The bulk charging mode typically involves providing a maximum charging current and / or a constant current to the battery. When the battery voltage has reached a limit voltage and / or a limit time, the bulk charging mode typically terminates, at which time the state of charge is approximately 80%.

[0006] The subsequent absorption charging mode or constant voltage mode typically applies a constant charging voltage and a decreasing charging current or a limited current for a certain period of time.

[0007] Once the battery has reached a second and higher state of charge, for example 96 - 98%, it typically enters the float charging mode. In the float charging mode, the voltage will taper down and be maintained at a stable voltage.

[0008] A disadvantage of such conventional battery chargers for vehicles is that for multi-purpose vehicles where charging is frequently started (for example, several times a day), the starter battery is frequently subjected to the absorption charging mode or the constant voltage charging mode. This shortens the battery life due to the battery being subjected to high charging voltage levels for long periods of time, which may, for example, result in unnecessary water loss in the battery.

[0009] Therefore, there is a need for an improved method of charging a vehicle battery.

[0010] Object of the present invention

[0011] The object of the embodiments of the present invention is to provide a solution to mitigate or solve the disadvantages described above. Summary of the invention

[0012] The above object is achieved by the subject matter described herein. Further advantageous embodiments of the present invention are described herein.

[0013] According to a first aspect of the present invention, the object of the present invention is achieved by a method performed by a battery charger configured to charge a vehicle battery, the method comprising: starting to charge the battery in a high-capacity charging mode at a first time point, determining, at a second time point after the first time point, that the charging of the battery in the high-capacity charging mode is completed, estimating, at the second time point, the state of charge of the battery at the first time point when starting to charge the battery in the high-capacity charging mode, and starting to charge the battery in a subsequent charging mode using the estimated state of charge, wherein the subsequent charging mode is selected from an absorption charging mode and a floating charging mode.

[0014] Advantages of this first aspect include at least an increased expected life of the charged vehicle battery. Especially when used in applications for multi-purpose vehicles.

[0015] According to a second aspect of the present invention, the object of the present invention is achieved by a battery charger configured to charge a vehicle battery, the charger comprising a processor and a memory, the memory containing instructions executable by the processor, whereby the charger is operable and / or configured to perform the method according to the first aspect.

[0016] According to a third aspect of the present invention, the object of the present invention is achieved by a computer program comprising computer-executable instructions for causing a battery charger to perform the method according to the first aspect when the computer-executable instructions are executed on a processing circuit included in the battery charger.

[0017] According to a fourth aspect of the present invention, the object of the present invention is achieved by a computer program product comprising a computer-readable storage medium having implemented therein the computer program according to the third aspect.

[0018] Advantages of the second to fourth aspects are at least the same as those for the first aspect.

[0019] The scope of the present invention is defined by the claims, which are incorporated into this section by reference. By considering the following detailed description of one or more embodiments, a more complete understanding of the embodiments of the present invention, and the realization of its additional advantages, will be given to those skilled in the art. Reference will be made to the accompanying drawings, which will be briefly described first. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Illustrates the behavior of a battery charger operating in a bulk charge mode according to one or more embodiments of the present disclosure.

[0021] Figure 2 Illustrates the behavior of a battery charger operating in an absorption charge mode according to one or more embodiments of the present disclosure.

[0022] Figure 3 Illustrates the behavior of a battery charger operating in a float charge mode according to one or more embodiments of the present disclosure.

[0023] Figure 4A Illustrates the behavior of a conventional battery charger.

[0024] Figure 4B Illustrates the behavior of a battery charger according to one or more embodiments of the present disclosure.

[0025] Figure 5 Illustrates the behavior of a battery charger in a state of relatively high-level charging according to one or more embodiments of the present disclosure.

[0026] Figure 6 Illustrates the behavior of a battery charger in a state of relatively low-level charging according to one or more embodiments of the present disclosure.

[0027] Figure 7 Shows a flowchart of a method according to one or more embodiments of the present disclosure.

[0028] Figure 8 Shows a battery charger according to one or more embodiments of the present disclosure.

[0029] By considering the following detailed description of one or more embodiments, a more complete understanding of the embodiments of the present invention, and the realization of its additional advantages, will be given to those skilled in the art. It should be understood that the same reference numerals are used to identify the same elements illustrated in one or more of the drawings. DETAILED DESCRIPTION

[0030] The present disclosure relates to battery chargers for vehicles, and more particularly to battery chargers for applications in which a starter battery and / or a service battery of a multi-purpose vehicle is charged. A typical characteristic of such applications is that charging is frequently initiated, e.g., several times a day. This is due to the fact that multi-purpose vehicles are often equipped with accessories that impose a load on the service and / or starter battery in the vehicle and thus deplete the battery over time. Such accessories can be, for example, on-board chargers for portable equipment such as flashlights, interior lighting, or climate control devices.

[0031] In a typical scenario, a multi-purpose vehicle such as a fire truck may be called out during the day to perform multiple tasks and will generally be directly reconnected to a battery charger upon returning to the fire station. Thus, in the case of an intelligent charger operating in a subsequent charging mode such as a bulk-absorption-float charging mode, one or more vehicle batteries are frequently subjected to the absorption charging mode, which shortens the battery life.

[0032] The present disclosure addresses this by estimating and taking into account, at the end of the bulk charging phase, the state of charge of the battery at the start of the bulk charging phase when charging is initiated. Based on this information, a decision is made as to whether absorption charging mode should be entered or whether charging should proceed directly to float charging mode.

[0033] In other words, the presently disclosed method makes a trade-off between the total charging time required and increasing the battery life. If the battery is in a relatively high state of charge at the start of charging, charging proceeds directly to float charging mode without subjecting the battery to the relatively high charging voltage used when charging the battery in absorption charging mode. If the battery is in a relatively low state of charge at the start of charging, charging proceeds to absorption charging mode before entering float charging mode.

[0034] In general, all terms used in this document should be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and / or implied from the context in which it is used. All references to an element, device, component, apparatus, step, etc. will be publicly interpreted as referring to at least one instance of the element, device, component, apparatus, step, etc., unless otherwise explicitly stated. The steps of any method disclosed herein need not be performed in the exact order disclosed, unless the steps are explicitly described as after or before another step, and / or where it is implied that the steps must be after or before another step. Whenever appropriate, any feature of any embodiment in the embodiments disclosed herein can be applied to any other embodiment. Similarly, any advantage of any embodiment in the embodiments can be applied to any other embodiment, and vice versa. From the following description, other objects, features, and advantages of the appended embodiments will be apparent.

[0035] The "or" in this specification and the corresponding claims should be understood to cover the mathematical OR of "and" and "or", and should not be understood as XOR (exclusive OR). The indefinite article "a" in this disclosure and the claims is not limited to "one", and can also be understood as "one or more", i.e., plural.

[0036] The term "battery charger" as used herein refers to an intelligent battery charger that is software-controlled and configured to operate in subsequent charging modes (such as a bulk-absorption-float charging mode). The battery charger includes a processor and / or processing circuitry that is software-controlled and controls the behavior of the charger, particularly the voltage and current output to the battery.

[0037] The term "battery" or "vehicle battery" as used herein refers to a battery suitable for inclusion in a vehicle and used as a service battery and / or a starter battery of the vehicle. It is to be understood that such a battery can be used in other applications without departing from the present disclosure.

[0038] The term "state of charge" or SoC as used herein refers to the capacity / state of charge of a battery related to the maximum and / or nominal capacity / state of charge of the battery, and is typically given as a percentage value of the maximum capacity of the battery. For example, SoC = 0% represents an empty battery, and SoC = 100% represents a fully charged battery capable of providing the maximum capacity of the battery.

[0039] The term "charging mode" as used herein refers to the behavior of an intelligent battery charger, particularly with respect to the charging voltage and charging current output.

[0040] The term "bulk charge mode" or "bulk charging" as used herein refers to the behavior of a charger. The bulk charge mode may also be referred to as a constant current charge mode because the battery charge current is maintained at a substantially constant value.

[0041] The term "absorption charge mode" or "absorption charging" as used herein refers to the behavior of a charger. The absorption charge mode may also be referred to as a constant voltage charge mode because the battery charge voltage is maintained at a substantially constant value.

[0042] The term "float charge mode" or "float charging" as used herein refers to the behavior of a charger. The float charge mode may also be referred to as a maintenance charge mode because the battery charge voltage is maintained at a substantially constant value (close to the nominal open circuit voltage and lower than the substantially constant value in the absorption charge mode). The float charge mode is mainly aimed for topping-up the battery capacity to 100% and compensating for the self-discharge of the battery.

[0043] Figure 1 Illustrated is the behavior of a battery charger operating in bulk charge mode according to one or more embodiments of the present disclosure. Figure 1 Illustrated are the charging voltage and charging current output from a battery charger operating in bulk charge mode, which are illustrated by curve U_Charge for the charging voltage and I_Charge for the charging current, respectively. At a first time point t_Bulk_Start, charging in bulk charge mode begins. The charging current is controlled and / or ramped up from substantially zero (0) amperes to a target constant charging current of I_Charge amperes. At a second time point t_Bulk_End, it is determined that charging in bulk charge mode is complete, for example, by determining that a first measured voltage across the poles of the battery is equal to or exceeds a voltage threshold U_Lim.

[0044] In one example, the battery charger is connected to two series-connected 12 V lead-acid batteries forming a 24 V battery pack. The battery voltage at the start of bulk charging is 23.2 volts. At the first time point t_Bulk_Start, a constant charging current of 10 amperes is provided to the battery pack, i.e., I_Charge = 10A. As can be seen in Figure 1 the battery voltage steadily increases until it reaches the voltage threshold U_Lim = 28.8 volts at the second time point t_Bulk_End. From historical observations of the battery charge curve, this means that the state of charge SoC has reached 80% at the second time point t_Bulk_End. In other words, the predetermined data indicates that the battery pack is at 80% SoC when the voltage threshold U_Lim reaches 28.8 volts.

[0045] Figure 2 Illustrates the behavior of a battery charger operating in an absorption charging mode or a constant voltage charging mode according to one or more embodiments of the present disclosure. Figure 2 Illustrates the charging voltage and charging current output from a battery charger operating in an absorption charging mode, where the charging voltage and charging current are illustrated by curves U_Charge and I_Charge, respectively. At a third time point t_Absorption_Start, charging in the absorption mode begins. The charging voltage is then controlled or maintained at a substantially constant voltage, such as at a voltage threshold U_Lim as described with respect to Figure 1 The charging current decreases or diminishes over time from a constant charging current I_Charge amperes as described with respect to Figure 1 The charging voltage is maintained for a predetermined period of time until a fourth time point t_Absorption_End. The predetermined period of time can be given by a relationship (e.g., a look-up table) that correlates the constant charging current used in the bulk charging mode I_Charge with the period of time. Examples of such periods of time are 8 hours for a charging current of 20 amperes, 6 hours for a charging current of 10 amperes, and 5 hours for a charging current of 8 amperes.

[0046] Figure 3 Illustrates the behavior of a battery charger operating in a floating charging mode according to one or more embodiments of the present disclosure. Figure 3 Illustrates the charging voltage and charging current output from a battery charger operating in a floating charging mode, where the charging voltage and charging current are illustrated by curves U_Charge and I_Charge, respectively. At a fifth time point t_Float_Start, charging in the floating mode begins. The charging voltage is then controlled or maintained at a substantially constant voltage, e.g., at a voltage close to the nominal open circuit voltage and lower than the constant voltage used in the absorption charging mode (e.g., lower than U_Lim as further described with respect to Figure 1 and Figure 2 The charging current is limited to a predetermined current equal to the expected self-discharge current and standby current. The constant charging voltage is maintained for a predetermined period of time until a sixth time point t_Float_End. The predetermined period of time can be limited to a maximum of 10 days or 240 hours.

[0047] In one example, the absorption charging mode has occurred before the floating charging mode, in which the charging voltage has been controlled or maintained at a substantially constant voltage, e.g., as described with respect to Figure 1at the described voltage threshold U_Lim. For example, at U_Lim = 28.8 volts. Then the charging voltage is allowed to smoothly drop to near the nominal open-circuit voltage, for example 27.2 volts, and the charging voltage then remains constant for the duration of the float charging mode.

[0048] Figure 4A illustrates the behavior of a conventional battery charger. Figure 4A illustrates the different charging modes in which a battery charger or intelligent battery charger subsequently operates. In other words, the charger initially operates in a bulk charging mode, then subsequently switches to operate in an absorption charging mode, and subsequently switches to operate in a float charging mode. An intelligent battery charger typically includes a processor and / or processing circuitry that is controlled by software and controls the behavior of the charger, particularly with respect to the charging voltage and charging current output.

[0049] A disadvantage of such a conventional intelligent battery charger for a vehicle is that for a usage scenario involving charging the battery of a multi-purpose vehicle where charging is frequently started (e.g., several times a day), one or more batteries are frequently subjected to the absorption charging mode, which shortens the battery life due to the long duration of the high charging voltage level, which may, for example, result in unnecessary water loss in the battery.

[0050] Figure 4B illustrates the behavior of a battery charger according to one or more embodiments of the present disclosure. As can be seen from Figure 4B Once the bulk charging mode is completed at the second time point t_Bulk_End, the state of charge of the battery at the first time point t_Bulk_Start when charging the battery in the bulk charging mode is determined or estimated.

[0051] In other words, once the bulk charging mode is completed at the second time point t_Bulk_End, it is known that the state of charge of the battery will be at 80%. This can be learned, for example, by studying predetermined data such as historical charging curves when charging a battery of a similar type. By estimating the state of charge of the battery at the start of the bulk charging mode, i.e., at the first time point t_Bulk_Start, it can be determined whether the estimated state of charge is relatively low or relatively high. In other words, it can be determined whether the battery is in a relatively high state of charge when starting the bulk charging or whether the battery is in a relatively low state of charge when starting the bulk charging.

[0052] In one example, a relatively high level of charge state can be considered as 75% or higher SoC, and a relatively low level of charge state can be considered as SoC below 75%. That is, when starting bulk charging, a 75% SOC threshold can be used to classify the level of the charge state. Any other suitable SoC threshold can be used to distinguish a relatively high level of SoC from a relatively low level of SoC.

[0053] Based on the information that the battery is in a relatively high level of SoC or the battery is in a relatively low level of SoC, a decision can then be made as to whether the battery charger should subsequently operate in an absorption charging mode when determining a relatively low level of charge state or whether the battery charger should subsequently operate in a floating charging mode when determining a relatively high level of charge state.

[0054] In other words, the currently disclosed method and battery charger trade off between the total charging time required and improving the battery life. If the battery is in a relatively high level of charge state at the start of charging, the charging proceeds directly to the floating charging mode without subjecting the battery to the relatively high charging current used when charging the battery in the absorption charging mode.

[0055] This has the advantage of extending the service life of the battery.

[0056] Figure 5 Illustrates the behavior of a battery charger in a relatively high level of charge state according to one or more embodiments of the present disclosure. Refer to Figure 1 、 Figure 3 and Figure 4B The battery charger ends operating in the bulk charging mode at a second time point t_Bulk_End. When starting to charge the battery in the bulk charging mode, the charge state of the battery is then estimated or determined for a first time point t_Bulk_Start. In the example in Figure 5 It is then determined that the charge state for the first time point t_Bulk_Start is equal to or higher than the SoC threshold, for example 75%, and is thus considered a relatively high level of charge state. Then, the battery charger selects and / or is controlled to operate in the floating charging mode as the subsequent charging mode. The subsequent charging mode is selected from the absorption charging mode and the floating charging mode.

[0057] Figure 6 Illustrates the behavior of a battery charger in a relatively low level of charge state according to one or more embodiments of the present disclosure. Refer to Figure 1 、 Figure 3 and Figure 4B, the battery charger ends operating in the bulk charging mode at a second time point t_Bulk_End. When starting to charge the battery in the bulk charging mode, the state of charge of the battery is then estimated or determined for a first time point t_Bulk_Start. In Figure 6 In the example of

[0058] it is understood that after the absorption charging mode is completed, the battery charger can subsequently operate in another charging mode, such as the float charging mode.

[0059] Figure 7 A flowchart of a method according to one or more embodiments of the present disclosure is shown. The method is performed by a battery charger configured to charge a vehicle battery. Regarding Figure 8 the battery charger is further described. The method includes:

[0060] Step 710: Start charging the battery in the bulk charging mode at a first time point t_Bulk_Start. It is understood that one or more other charging modes may precede the bulk charging mode, such as a battery test mode, a soft charging mode, and a desulfation mode.

[0061] In other words, start the constant current charging mode.

[0062] Step 720: Determine that the charging of the battery in the bulk charging mode is completed at or near a second time point t_Bulk_End after the first time point t_Bulk_Start.

[0063] In one embodiment, when a first measured voltage at the poles of the battery is equal to or exceeds a voltage threshold U_Lim, it is determined that the bulk charging mode is completed.

[0064] In one example, the voltage threshold U_Lim is set to 28.8 volts, and other example thresholds may be 29.4 volts or 14.4 and 14.7 volts.

[0065] Step 730: Estimate the state of charge of the battery at the first time point t_Bulk_Start when starting to charge the battery in the bulk charging mode at or immediately following the second time point t_Bulk_End.

[0066] In other words, estimating the SoC at the start of bulk charging enables later determination of whether the battery is at a relatively high level of SoC at the start of bulk charging or whether the battery is at a relatively low level of SoC at the start of bulk charging.

[0067] In a first embodiment, a first relationship that depends at least on time is used to estimate the state of charge SoC_Bulk_Start of the charging. In other words, the time difference between a first time point t_Bulk_Start and a second time point t_Bulk_End is used to select a subsequent charging mode of the battery charger. In this embodiment, the first relationship depends on the selection of any one of a predetermined state of charge SoC_Bulk_End of the charging, a predetermined charging current I_Charge used in the bulk charging mode, the nominal capacity CAP_Battery of the battery, and the difference Δt between the first time point and the second time point.

[0068] In one example, the predetermined state of charge SoC_Bulk_End of the charging is 80%. The predetermined charging current I_Charge is obtained / retrieved as a parameter stored in the memory of the battery charger. The nominal capacity CAP_Battery of the battery is obtained / retrieved as a parameter stored in the memory of the battery charger and / or obtained by performing measurements on the battery, for example, as further described in Swedish patents SE 540542 and S541171, which are hereby incorporated by reference.

[0069] Additionally and / or alternatively, the relationship SoC_Bulk_Start = SoC_Bulk_End - ((Δt * I_Charge) / CAP_Battery) is used to estimate the state of charge SoC_Bulk_Start of the charging, where SoC_Bulk_Start is the estimated state of charge, SoC_Bulk_End is the predetermined state of charge, Δt is the time difference between the first time point and the second time point, I_Charge is the charging current used in the bulk charging mode, and CAP_Battery is the nominal capacity of the battery.

[0070] Additionally and / or alternatively, the predetermined state of charge SoC_Bulk_End of the charging is derived from a charging curve associated with the battery, for example, an SoC of 80%. In other words, the SoC at the second time point t_Bulk_End.

[0071] In another embodiment, a charge current integration method (i.e., "Coulomb counting") is used to estimate the state of charge SoC_Bulk_Start, where the SoC is calculated by measuring the charge current and integrating it over time. For example, between a first time point t_Bulk_Start and a second time point t_Bulk_End.

[0072] In other words, the relative SoC change that occurs between the first time point t_Bulk_Start and the second time point t_Bulk_End can be estimated, and the state of charge SoC_Bulk_Start is estimated by subtracting the relative SoC change from the known SoC of 80% at the second time point t_Bulk_End.

[0073] In another embodiment, the open circuit voltage OCV of the battery is used and a predetermined data (such as a look-up table) is used to estimate the SoC to estimate the state of charge SoC_Bulk_Start. In this embodiment, the state of charge SoC_Bulk_Start is estimated by measuring the open circuit voltage OCV of the battery at the first time point t_Bulk_Start and using a predetermined relationship and the measured OCV to estimate the state of charge SoC_Bulk_Start. Optionally, the OCV can be obtained as a rest OCV value by obtaining the OCV value after the battery has been allowed to rest (e.g., after several hours up to 24 hours).

[0074] In one example, a predetermined look-up table is provided for mapping the OCV to the SoC. The predetermined look-up table can be obtained, for example, by studying the historical charging of the battery (such as the historical charging curve obtained when charging a similar type of battery).

[0075] Regarding another embodiment, the measured battery voltage or the trend of the voltage on the poles of the battery is used to estimate the state of charge SoC_Bulk_Start. In this embodiment, the state of charge SoC_Bulk_Start is estimated by measuring a plurality of battery voltage values at a plurality of time points after the first time point t_Bulk_Start. In addition, the plurality of measured battery voltage values are used to determine the voltage trend over time. Then the charging current I_Charge is estimated based on a second relationship, where the second relationship depends on the voltage trend over time and the predetermined state of charge SoC_Bulk_End at the second time point t_Bulk_End.

[0076] This embodiment is further described in Swedish patents SE540603 and SE540073, which are incorporated herein by reference.

[0077] Step 740: Charge the battery in a subsequent charging mode starting with the estimated state of charge SoC_Bulk_Start, where the subsequent charging mode is selected from an absorption charging mode and a floating charging mode.

[0078] In one embodiment, starting to charge the battery in a subsequent charging mode includes: if the estimated state of charge SoC_Bulk_Start is less than the state of charge threshold SoC_Lim, start charging the battery in an absorption charging mode after a bulk charging mode, or if the estimated state of charge SoC_Bulk_Start is equal to or greater than the state of charge threshold SoC_Lim, start charging the battery in a floating charging mode after a bulk charging mode. In one example, the state of charge threshold SoC_Lim is set to 75%.

[0079] In other words, if the estimated state of charge SoC_Bulk_Start is determined to be equal to or greater than the state of charge threshold SoC_Lim, it is determined that the estimated state of charge SoC_Bulk_Start is relatively high. If the estimated state of charge SoC_Bulk_Start is determined to be less than the state of charge threshold SoC_Lim, it is determined that the estimated state of charge SoC_Bulk_Start is relatively low.

[0080] In one embodiment, a computer program is provided and the computer program includes computer-executable instructions that, when executed on a processor and / or processing circuit / circuitry included in a battery charger 800, cause the battery charger 800 to perform any of the method steps described herein.

[0081] In one embodiment, a computer program product is provided and the computer program product includes a computer-readable storage medium having the above computer program implemented therein.

[0082] Figure 8FIG. 800 shows a battery charger according to one or more embodiments of the present disclosure. The battery charger 800 may be in the form of, for example, an electronic battery charger, a server, an in-vehicle computer, a fixed computing device, a laptop computer, a tablet computer, a handheld computer, a wrist-worn computer, a smart watch, a smart phone, or a smart TV. The battery charger 800 may include a processor / processing circuitry 812 that is communicatively coupled to a communication interface 804, such as a transceiver configured for wired or wireless communication. The battery charger 800 may further include at least one optional antenna (not shown in the figure). The antenna may be coupled to the transceiver and configured to transmit and / or emit and / or receive wired or wireless signals in a communication network such as WiFi, Bluetooth, 3G, 4G, 5G, etc.

[0083] In one example, the processing circuitry 812 may be any one of a processing circuitry and / or a central processing unit and / or a processor module and / or a plurality of processors configured to cooperate with each other.

[0084] In addition, the battery charger 800 may further include a memory 815. The memory 815 may include, for example, a hard disk RAM, a disk drive, a floppy disk drive, a flash drive, or other removable or fixed media drives or any other suitable memory known in the art. The memory 815 may contain instructions executable by the processing circuitry to perform any of the steps or methods described herein.

[0085] The processing circuitry 812 may optionally be communicatively coupled to any one of the communication interface 804, the memory 815, one or more sensors (such as a battery voltage sensor that measures the battery voltage on the poles of the battery). The battery charger 800 may be configured to send / receive control signals directly to any of the above-mentioned units or to an external node, or be configured to send / receive control signals via a wired and / or wireless communication network.

[0086] The communication interface 804, such as a wired / wireless communication network adapter and / or a wired / wireless transceiver, may be configured to send and / or receive data values or parameters as signals to or from the processing circuitry 812 to or from other external nodes. For example, measured battery voltage values. In an embodiment, the communication interface 804 communicates directly with an external node or via a wireless communication network.

[0087] In one or more embodiments, the battery charger 800 may further include an input device 817 that is configured to receive an input or an indication from a user and send a user input signal indicating the user input or indication to the processing circuitry 812.

[0088] In one or more embodiments, the battery charger 800 may further include a display 818 configured to receive from the processing circuitry 812 a display signal indicative of a rendered object, such as a text or a graphical user input object, and display the received signal as an object, such as a text or a graphical user input object.

[0089] In one embodiment, the display 818 is integrated with the user input device 817 and is configured to receive from the processing circuitry 812 a display signal indicative of a rendered object, such as a text or a graphical user input object, and display the received signal as an object, such as a text or a graphical user input object, and / or is configured to receive an input or indication from the user and send a user input signal indicative of the user input or indication to the processing circuitry 812.

[0090] In further embodiments, the battery charger 800 may further include and / or be coupled to one or more additional sensors (not shown in the figures) configured to receive and / or obtain and / or measure physical characteristics related to the battery and / or the battery charger and send one or more sensor signals indicative of the physical characteristics of the battery and / or the battery charger to the processing circuitry 812. For example, an external voltage sensor that measures the battery voltage and / or the ambient temperature.

[0091] In further embodiments, the battery charger 800 is configured to communicatively and / or electrically connect to the battery 820, for example, via a battery clip, a cable, and a connector. The battery charger 800 then outputs a charging voltage and a charging current to the battery 820 via the communication and / or electrical connection.

[0092] In further embodiments, the battery charger 800 includes a controllable power supply 819 configured to output a charging voltage and a charging current to the battery 820 based on a control signal received from the processing circuitry 812. The controllable power supply 819 generally provides the charging voltage and the charging current to the battery 820 via a coupling device (e.g., via a battery clip, a cable, and a connector).

[0093] In one or more embodiments, the processing circuitry 812 is further communicatively coupled to the communication interface 804 and / or the input device 817 and / or the display 818 and / or the controllable power supply 819 and / or the sensors and / or the additional sensors and / or any of the units described herein.

[0094] In one embodiment, a battery charger (800) is provided, which is configured to charge a vehicle battery (820). The charger includes a processor (812) and a memory (815). The memory contains instructions executable by the processor, whereby the charger (800) is operable and / or configured to perform any of the method steps described herein.

[0095] In an embodiment, the communication network uses wired or wireless communication technologies for communication, which may include at least one of the following: Local Area Network (LAN), Metropolitan Area Network (MAN), Global System for Mobile Communications (GSM), Enhanced Data GSM Environment (EDGE), Universal Mobile Telecommunications System, Long Term Evolution, High Speed Downlink Packet Access (HSDPA), Wideband Code Division Multiple Access (W-CDMA), Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Bluetooth®, Zigbee®, Wi-Fi, Voice over Internet Protocol (VoIP), Advanced LTE, IEEE802.16m, Advanced WirelessMAN, Evolved High Speed Packet Access (HSPA+), 3GPP Long Term Evolution (LTE), Mobile WiMAX (IEEE802.16e), Ultra Mobile Broadband (UMB) (formerly Evolution-Data Optimized (EV-DO) Revision C), Fast Low Latency Access Orthogonal Frequency Division Multiplexing with Seamless Handoff (Flash-OFDM), High Capacity Space Division Multiple Access (iBurst®), and Mobile Broadband Wireless Access (MBWA) (IEEE 802.20) systems, High Performance Radio Metropolitan Area Network (HIPERMAN), Beam Division Multiple Access (BDMA), Worldwide Interoperability for Microwave Access (Wi-MAX), and ultrasonic communication, among others, but not limited thereto.

[0096] Furthermore, those skilled in the art will recognize that the battery charger (800) may include the necessary communication capabilities in the form of, for example, functions, devices, units, elements, etc., for implementing this solution. Examples of other such devices, units, elements, and functions are: processors, memories, buffers, control logic, encoders, decoders, rate matchers, de-rate matchers, mapping units, multipliers, decision units, selection units, switches, interleavers, de-interleavers, modulators, demodulators, inputs, outputs, antennas, amplifiers, receiver units, transmitter units, DSPs, MSDs, TCM encoders, TCM decoders, power units, power feeds, communication interfaces, communication protocols, etc., which are appropriately arranged together for implementing this solution.

[0097] In particular, the processing circuitry and / or processing device of the present disclosure may include one or more instances of processing circuitry, a processor module and multiple processors configured to cooperate with each other, a central processing unit (CPU), a processing unit, processing circuitry, a processor, an application specific integrated circuit (ASIC), a microprocessor, a field programmable gate array (FPGA), or other processing logic that can interpret and execute instructions. Thus, the expressions "processing circuitry" and / or "processing device" may represent a processing circuitry including multiple processing circuits (such as, for example, any, some, or all of the processing circuits mentioned above). The processing device may further perform: data processing functions for input, output, and processing of data including data buffering; and device control functions such as user interface control or the like.

[0098] Finally, it should be understood that the present invention is not limited to the embodiments described above, but also relates to and incorporates all embodiments within the scope of the appended independent claims.

Claims

1. A method performed by a battery charger configured to charge a vehicle battery, the method comprising: starting to charge the battery in a bulk charge mode at a first time point t_Bulk_Start; determining that charging of the battery in the bulk charge mode is complete at a second time point t_Bulk_End after the first time point t_Bulk_Start; estimating a state of charge of the battery at the first time point t_Bulk_Start when starting to charge the battery in the bulk charge mode at the second time point t_Bulk_End; starting to charge the battery in a subsequent charge mode using the estimated state of charge SoC_Bulk_Start, wherein the subsequent charge mode is selected from an absorption charge mode and a float charge mode; wherein starting to charge the battery in the subsequent charge mode comprises: if the estimated state of charge SoC_Bulk_Start is less than a state of charge threshold SoC_Lim, starting to charge the battery in the absorption charge mode; or if the estimated state of charge SoC_Bulk_Start is equal to or greater than the state of charge threshold SoC_Lim, starting to charge the battery in the float charge mode.

2. The method according to claim 1, wherein estimating the state of charge SoC_Bulk_Start using a first relationship that depends at least on time, wherein the first relationship depends on a predetermined state of charge SoC_Bulk_End indicating completion of charging of the battery in the bulk charge mode, a predetermined charging current I_Charge used in the bulk charge mode, a nominal capacity CAP_Battery of the battery, and a difference Δt between the first time point and the second time point; 3. The method according to claim 2, wherein, estimating the state of charge SoC_Bulk_Start using the following relationship: SoC_Bulk_Start = SoC_Bulk_End - ((Δt * I_Charge) / CAP_Battery), where SoC_Bulk_Start is the estimated state of charge, SoC_Bulk_End is the predetermined state of charge, Δt is the time difference between the first time point and the second time point, I_Charge is the charging current used in the bulk charge mode, and CAP_Battery is the nominal capacity of the battery.

4. The method according to claim 2 or 3, wherein The predetermined state of charge SoC_Bulk_End is derived from a charge curve associated with the battery.

5. The method according to claim 1 or 2, wherein estimating the state of charge SoC_Bulk_Start by: measuring an open circuit voltage OCV of the battery at the first time point t_Bulk_Start, and estimating the state of charge SoC_Bulk_Start using the measured OCV with a predetermined relationship to provide the estimated state of charge.

6. The method according to claim 1 or 2, wherein estimating the state of charge SoC_Bulk_Start by: measuring a plurality of battery voltage values at a plurality of time points after the first time point t_Bulk_Start, determining a voltage trend over time using the plurality of battery voltage values, Obtain a charging current I_Charge for use in a high-capacity charging mode.

7. The method according to claim 1 or 2, wherein When a first measured voltage at a pole of the battery is equal to or exceeds a voltage threshold U_Lim, determine that the high-capacity charging mode is complete.

8. A battery charger (800) configured to charge a vehicle battery (820), the charger comprising: a processor (812), and a memory (815) containing instructions executable by the processor, whereby the charger (800) is operable and / or configured to perform the method according to any one of claims 1-7.

9. A computer program comprising computer-executable instructions for causing a battery charger (800) to perform the method according to any one of claims 1-7 when the computer-executable instructions are executed on a processing circuit included in the battery charger (800).

10. A computer program product comprising a computer-readable storage medium having implemented therein the computer program according to claim 9.

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