Method and system for determining the health status of a battery, control device

Abstract

The invention relates to a method and a system (10) for determining the health status (200) of a battery (4) of a vehicle (1) by means of a self-diagnostic function (100) of the vehicle (1) and a control device (6) for the battery (4). The method and the system (100) are configured such that the health status (200) of the battery (4) is determined by means of the self-diagnostic function (100) based on at least one statistical battery parameter (202.1n) and at least one temporal battery parameter (202.2n).

Description

[0001] The invention relates to a method and a system for determining a state of health of a battery and a control device for a battery.

[0002] The value of a used electric vehicle generally depends on the battery's health. Historical information about the battery's history is often lacking. Typically, only a few electrical properties, such as cold-cranking power, residual capacity, and charge acceptance, are measured and analyzed to determine battery health. The actual, current residual capacity is determined, for example, by the battery's complete discharge. These measurement and analysis methods are very complex, time-consuming, and only allow for a rough estimate of the battery's health.

[0003] In addition, there are complex testing procedures in the form of a battery test for electric vehicles, in which the battery is fully charged and then the vehicle is driven on a test bench under normal operation until the battery charge level drops below 10%. During the test phase, battery data is recorded and evaluated, and a battery certificate is issued after a few days.

[0004] From DE 10 2022 111 652 A1, for example, a method for determining a state of health of at least one battery cell of an electrical energy storage device is known, in which a current pulse is generated by means of an electrical resistance sink and the generated current pulse is transmitted to the at least one battery cell, wherein a voltage response corresponding to the current pulse is detected by means of an electronic computing device and the state of health is determined on the basis of the voltage response.

[0005] From DE 10 2016 209 848 A1 a system and a method for estimating the performance of battery systems are known, wherein an initial battery voltage is determined when the battery is operated at a current limit, and a future battery current is determined at a first time when the battery is operated at an associated voltage limit, on the basis of an initial battery current.

[0006] From DE 10 2020 214 182 A1 a method is known for determining an aging state of a device battery of a battery-operated device, in particular a vehicle battery of an electrically operated vehicle, taking into account calendar aging, with the following steps: After determining the start of an inactivity phase, determining a state of charge and a battery temperature at regular times; Upon activation of the device, providing a calendar aging state depending on a battery temperature profile resulting from the measured battery temperatures during the inactivity phase, and depending on a charge state profile determined from one or more of the charge states measured during the inactivity phase, using a predetermined aging state model.

[0007] The invention is based on the object of providing an improved method and an improved system for determining the health status of a battery, which are particularly simple and robust. Furthermore, a simple control device or control apparatus for the battery is to be provided.

[0008] The first-mentioned object is achieved according to the invention by a method for determining a state of health of a battery having the features of claim 1. The second-mentioned object is achieved according to the invention by a system for determining a state of health of a battery having the features of claim 6. The third-mentioned object is achieved according to the invention by a control device having the features of claim 4.

[0009] Advantageous embodiments of the invention are the subject of the subclaims.

[0010] The inventive method for determining the health status of a battery of a vehicle, for example, a hybrid or electric vehicle, provides a self-diagnosis function of the vehicle, wherein the self-diagnosis function determines the health status of the battery based on at least one statistical battery parameter and at least one temporal battery parameter. According to the invention, the statistical battery parameter(s) and / or the temporal battery parameter(s) are each weighted using an individual weighting factor, wherein the health status is determined according to one of the following equations: Health = 100−(((A / B)*100 / 4)+((C / D)*100 / 4)+((E / F)*100 / 4+((G / F)*100 / 4))or 100−(((A / B)*100 / k1)+((C / D)*100 / k2)+((E / F)*100 / k3+((G / F)*100 / k4)) with (1 / k1+1 / k2+1 / k3+1 / k4)=1, where A = number of fast charging processes, B = number of charging processes, C = duration with maximum charge level, D = battery life, E = duration of a charge level between 20% and 80% battery capacity, F = duration of rest phases and G = duration of battery temperature of >= -15°C

[0011] A battery is understood here in particular to be a rechargeable electrochemical energy storage device; the battery can also be referred to as an accumulator.

[0012] The invention is based on the idea of ​​a self-diagnosis function of the vehicle in order to avoid complex vehicle testing or complex real-time monitoring.

[0013] In particular, according to one aspect, the self-diagnosis function provides for recording the number of charging cycles and / or the number of discharging cycles of the battery as a statistical battery parameter and for determining and temporally evaluating at least one further battery parameter, for example, how quickly a particular battery charge is reached and / or evaluating the level of charge during a rest phase or a standing break, or the like. In particular, such easily determined battery parameters can be summarized or compiled and used to derive the state of health.

[0014] Such a method of determining the health status through the vehicle's self-diagnosis function can be carried out simply and quickly, in particular, the diagnostic data can be determined quickly and does not require additional testing equipment, thus saving costs.

[0015] According to one aspect, a number of rapid charging processes performed on the battery, a number of charging processes, in particular those performed normally, is or are determined as at least one statistical battery parameter, and charging cycles and / or discharging cycles are evaluated. For example, with regard to rapid charging processes, it is recorded how quickly a particular battery charge is reached.

[0016] According to one aspect, a duration of a maximum state of charge, a state of charge during a rest phase, a duration of a rest phase, a battery lifespan, and an average battery temperature gradient over a period of time can be considered and evaluated as at least one temporal battery parameter when diagnosing the health status. For example, the state of charge during the rest phase or during a standing break is determined.

[0017] Furthermore, according to one aspect, the statistical battery parameter(s) and the temporal battery parameter(s) can be weighted according to their number, in particular equally weighted. For example, the battery parameters considered are evaluated with an identical weighting factor.

[0018] The battery parameters taken into account can be weighted using the corresponding individual weighting factors in such a way that the sum of all individual weighting factors is equal to one.

[0019] In a possible further training, the self-diagnosis function includes the following steps: - Checking the current battery status for charging or rest phase, - when a charging phase is identified, monitoring the charging phase, determining the type of charging of the battery, whether a rapid charging process or a normal charging process is being carried out, and transmitting appropriate charging information to a control device when the charging phase is completed, or - when a rest period is identified, monitoring the charge level and temperature during the rest period and transmitting corresponding rest information to a control device when the rest period is ended, - Determining a health status or updating a stored health status, for example in a database, based on the charging information and / or the resting information, and - Saving health status, charging information and rest information.

[0020] The health status according to the invention is determined according to one of the following equations: Health status= 100−(((A / B)*100 / k)+((C / D)*100 / k)+((E / F)*100 / k+((G / F)*100 / k+)) with k= natural number greater than 0, for example k=4, or 100−(((A / B)*100 / k1)+((C / D)*100 / k2)+((E / F)*100 / k3+((G / F)*100 / k4)) with (1 / k1+1 / k2+1 / k3+1 / k4)=1 where A = number of fast charges, B = number of charges, C = duration at maximum charge level, D = battery life, E = duration of charge level between 20% and 80% battery capacity, F = duration of rest periods, and G = duration of battery temperature >= -15°C, for example, in a range of -16°C to -25°C, for example, a battery temperature of -20°C. The health status is expressed as a percentage from 0% to 100%, for example, 60%.

[0021] A control device according to the invention for the battery, in particular a high-voltage battery of the vehicle (also called a battery control unit), is characterized by the previously described self-diagnosis function for diagnosing the health status of the battery, wherein the self-diagnosis function determines the health status using the method according to the invention. The self-diagnosis function can be implemented as software.

[0022] The control device may be a control unit.

[0023] According to one embodiment, the control device may further comprise a communication interface, in particular a wired interface, in particular a CAN interface or a cable connection, and / or a wireless interface, for example a Bluetooth interface, a WLAN interface or the like, for transmitting the determined state of health of the battery to a cloud-based server or a central processing unit, in particular at a vehicle manufacturer.

[0024] The system according to the invention for determining the health status of the battery by means of the self-diagnosis function of the vehicle described above is characterized by the vehicle having the at least one control device described above, a charging station for charging the battery, a mobile device of a user of the vehicle and a cloud-based server, wherein the health status of the battery determined by means of the self-diagnosis function can be read out by the control device and / or the cloud-based server by means of the mobile device, in particular a mobile telephone, smartphone or a mobile tablet, by means of application software and can optionally be output on the mobile device.

[0025] Such a system, for example, allows a vehicle buyer to quickly and easily obtain information about the battery condition of the vehicle they are about to purchase. This can increase customer confidence in the condition of a vehicle battery and customer satisfaction when purchasing a vehicle. Furthermore, the condition of a vehicle battery can be transparently documented.

[0026] Embodiments of the invention are explained in more detail below with reference to drawings.

[0027] Showing: Fig. 1 schematically shows a system comprising a vehicle with a control device having a self-diagnosis function and a mobile device for reading a health status of a battery of the vehicle, Fig. 2 schematically shows the system with a detailed view of the control device for determining the health status of the battery, and Fig. 3 schematically shows a flow diagram of a method for determining the health status of the battery.

[0028] Corresponding parts are provided with the same reference numerals in all figures.

[0029] Fig. 1 schematically shows a system 10 with a vehicle 1 with a self-diagnosis function 100, a cloud-based server 3 and a mobile device 2 for reading a health status 200 of a battery 4 of the vehicle 1.

[0030] Vehicle 1 is, for example, an electric vehicle or a hybrid vehicle with a high-performance battery. Battery 4 can be, for example, a lithium accumulator.

[0031] The mobile device 2 is, for example, a mobile phone, smartphone or tablet.

[0032] The vehicle 1 comprises, for example, a control device 6, in particular a battery control unit, on which the self-diagnosis function 100 is implemented as software.

[0033] The vehicle 1 and / or the control device 6 as well as the mobile device 2 each comprise a communication interface 8 for exchanging data, in particular battery parameters 202.n, for example at least one statistical battery parameter and / or at least one temporal battery parameter, and the state of health 200. The respective communication interface 8 can be configured for a wireless communication connection 102 between the vehicle 1 and the mobile device 2. In addition, a wireless communication connection 102 can be provided between the vehicle 1, in particular the control device 6, and a diagnostic device 9, in particular an on-board diagnostic device, for exchanging data, in particular battery parameters 202.n and the state of health 200.

[0034] By means of the self-diagnosis function 100, the health status 200 of the battery 4 can be determined based on at least one statistical battery parameter 202.1n and at least one temporal battery parameter 202.2n.

[0035] For example, the self-diagnosis function 100 provides for recording the number of charging cycles 204 and / or the number of discharging cycles 206 of the battery 4 as a statistical battery parameter 202.1n, and for determining and temporally evaluating at least one further battery parameter 202.n, for example, how quickly a particular battery charge 208 is reached and / or evaluating the level of a state of charge 210 during the rest phase 220 or during a standstill period, or the like. In particular, such determined battery parameters 202.n can be summarized or compiled and used to derive the state of health 200.

[0036] In particular, a number of rapid charging processes 212 of the battery 4, a number of charging processes 214, in particular those carried out normally, can be determined as at least one of the statistical battery parameters 202.1n, and charging cycles 204 and / or discharging cycles 206 can be evaluated. For example, with regard to the rapid charging processes 212, it is recorded how quickly which battery charge 208 is reached.

[0037] Alternatively or additionally, a duration 216 of a maximum state of charge 218, the state of charge 210 during a rest phase 220, a duration 222 of the rest phase 220, a battery life 224, and an average battery temperature gradient 226 over a predetermined period 228 can be considered and evaluated as at least one temporal battery parameter 202.2n when diagnosing the health status 200. For example, the level of the state of charge 218 during the rest phase 220 (also called the standing break or standing phase) is determined.

[0038] Furthermore, the statistical battery parameter(s) 202.1n and the temporal battery parameter(s) 202.2n can be weighted according to their number, in particular equally weighted. For example, the considered battery parameters 202.n are evaluated with an identical weighting factor k.

[0039] Alternatively, the statistical battery parameter(s) 202.1n and / or the temporal battery parameter(s) 202.2n can each be weighted using an individual weighting factor k1 to k4. The considered battery parameters 202.n can be weighted using the associated individual weighting factors k1 to k4 such that the sum of all individual weighting factors k1 to k4 is equal to one.

[0040] Fig. 2 schematically shows the system 10 with the vehicle 1 and the at least one control device 6 for determining the health status 200 of the battery 4.

[0041] The battery 4 is an accumulator that can be charged by means of a charging station 7 using a rapid charging process 212 or a normal charging process 214.

[0042] The control device 6 is, in particular, a battery control unit or a diagnostic control unit 6.1, which additionally communicates via a wired communication connection 104 with a central driving and charging controller 6.2 (CDCC = Central Driving and Charging Controller) and / or a communication control unit 6.3 (also called a Telematic ECU) for exchanging battery parameters 202.n. The communication control unit 6.3 is configured to communicate with the cloud-based server 3 via the wireless communication connection 102.

[0043] Fig. Figure 3 schematically shows a flow diagram of a method for determining the health status 200 of the battery 4 by means of the self-diagnosis function 100 of the control device 6, for example the driving and charging control unit 6.2 (shown in Fig. 2).

[0044] The self-diagnosis function 100 may include the following steps: In a first step 300, the driving and charging control unit 6.2 is in a standby mode or sleep mode, and starts the self-diagnosis function 100 upon a request from a user, for example via a request from the mobile device 2 or a diagnostic device 9.

[0045] In a second step 301, a request to provide data and information, in particular the battery parameters 202.n, which are detected, for example, in a third step 302 by a vehicle sensor system or read from a memory or database, as well as a condition check of the battery 4 in a fourth step 303 is activated.

[0046] In this case, the battery 4 is monitored either for a charging phase or a charging process in a further step 304 or for a rest phase in step 305 as well as its temperature in the rest phase in a further step 306.

[0047] In particular, in step 304, when a charging phase is identified, this is monitored, for example, to determine whether a rapid charging process 212 or a normal charging process 214 is currently being carried out, and, if it is determined in step 307 that the charging phase has ended, corresponding charging information is transmitted to the driving and charging control unit 6.2 for determining the state of health 200 in step 308.

[0048] Furthermore, in step 305, for example, when the rest phase is identified, the state of charge 210 during the rest phase and the battery temperature during the rest phase are monitored and, if it is identified in step 309 that the rest phase has ended, corresponding rest information is transmitted to the driving and charging control unit 6.2 for determining the state of health 200 in step 308.

[0049] In step 308, the health status 200 is determined or updated based on the charging information and / or the resting information and stored in step 310, for example in a memory or a database.

[0050] The health status 200 is determined in step 308 according to one of the following equations: Health status 200 = 100 − (((A / B) * 100 / k) + ((C / D) * 100 / k) + ((E / F) * 100 / k + ((G / F) * 100 / k)) with k = natural number greater than 0, for example k = 4, or 100 − (((A / B) * 100 / k1) + ((C / D) * 100 / k2) + ((E / F) * 100 / k3 + ((G / F) * 100 / k4)) with (1 / k1 + 1 / k2 + 1 / k3 + 1 / k4) = 1 where A = number of fast charges 212, B = number of charges 214, C = duration at maximum charge level 218, D = battery life 224, E = duration of a charge level 210 between 20% and 80% battery capacity, F = duration (222) of rest periods (220) and G = duration of battery temperature of >= -15°C, for example a battery temperature in a range of -16°C to -25°C, for example a battery temperature of -20°C. The health level 200 can be specified as a percentage from 0% to 100%.

[0051] The self-diagnosis function 100 is then deactivated and the drive and charging control unit 6.2 is reset to step 300 and thus put back into a standby or idle state.

[0052] The advantages described herein with respect to the method may also relate to the system and control device described herein and vice versa. List of reference symbols 1 vehicle 2 mobile device 3 cloud-based servers 4 Battery 6 Control device 6.1 Diagnostic control unit 6.2 Driving and charging control unit 6.3 Communication control unit 7 Charging station 8 Communication interface 9 Diagnostic device 10 systems 100 self-diagnosis function 102 wireless communication connection 104 Wired communication connection 200 Health status 202.n Battery parameters 202.1n statistical battery parameters 202.2n temporal battery parameters 204 charging cycles 206 discharge cycles 208 Battery charge 210 Charge level 212 Fast charging process 214 Charging process 216 Duration 218 maximum charge level 220 Rest phase 222 duration 224 Battery life 226 Battery temperature gradient 228 specified time period 300 to 310 steps k1, k2, k3, k4 weighting factor(s)

Claims

[1] Method for determining a state of health (200) of a battery (4) of a vehicle (1) by means of a self-diagnosis function (100) of the vehicle (1), wherein the state of health (200) of the battery (4) is determined by means of the self-diagnosis function (100) on the basis of at least one statistical battery parameter (202.1n) and at least one temporal battery parameter (202.2n), wherein the statistical battery parameter(s) (202.1n) and / or the temporal battery parameter(s) (202.2n) are each weighted using an individual weighting factor (k1 to k4), characterized by that the state of health (200) is determined according to one of the following equations: Health(200)= 100−(((A / B)*100 / 4)+((C / D)*100 / 4)+((E / F)*100 / 4+((G / F)*100 / 4))or 100−(((A / B)*100 / k1)+((C / D)*100 / k2)+((E / F)*100 / k3+((G / F)*100 / k4)) with (1 / k1+1 / k2+1 / k3+1 / k4)=1, with A = number of fast charges (212), B = number of charges (214), C = duration with maximum charge level (218), D = battery life (224), E = duration of a charge level (210) between 20% and 80% battery capacity, F = duration (222) of rest phases (220) and G = duration of battery temperature of >= -15°C. [2] Method according to one of the preceding claims, characterized by that the statistical battery parameter(s) (202.1n) and the temporal battery parameter(s) (202.2n) are weighted equally according to their number. [3] Method according to one of the preceding claims, characterized by that the self-diagnosis function (100) comprises the following steps (300 to 310): - Checking the current battery status for charging or rest phase, - upon identification of a charging phase, monitoring the charging phase, determining the type of charging of the battery (4), whether a rapid charging process (212) or a normal charging process (214) is being carried out, and transmitting corresponding charging information to a control device (6) when the charging phase is completed, or - upon identification of a rest phase, monitoring the charge state (210) and the temperature during the rest phase and transmitting corresponding rest information to a control device (6) when the rest phase is ended, - determining a health status (200) or updating a stored health status (200) based on the charging information and / or the resting information, and - Saving the health status (200), charging information and rest information. [4] Control device (6) for a battery (4), in particular a high-voltage battery of a vehicle (1), characterized bya self-diagnosis function (100) for the battery (4) for diagnosing a state of health (200) of the battery (4), wherein the self-diagnosis function (100) determines the state of health (200) by means of the method according to one of claims 1 to 3. [5] Control device (6) according to claim 4, characterized by a communication interface (8) for transmitting the determined health status (200) of the battery (4) to a cloud-based server (3). [6] System (10) for determining a state of health (200) of a battery (4) of a vehicle (1) by means of a self-diagnosis function (100) of the vehicle (1), characterized byat least one vehicle (1) with a control device (6) according to claim 4 or 5, a charging station (7) for charging the battery (4), a mobile device (2) of a user of the vehicle (1) and a cloud-based server (3), wherein the health status (200) of the battery (4) determined by means of the self-diagnosis function (100) can be read out by means of the mobile device (2) by the control device (6) and / or by the cloud-based server (3).

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