Patent Publication Number: US-2021194261-A1

Title: Battery controller and battery level measurement method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Taiwan Application Serial Number 108147173, filed Dec. 23, 2019, which is herein incorporated by reference in its entirety. 
     BACKGROUND 
     Field of Invention 
     The present invention relates to a battery controller. More particularly, the present invention relates to a battery controller and a battery level measurement method thereof. 
     Description of Related Art 
     Nowadays, calculation of battery level is the important function for electronic products. The traditional unitary estimation method will cause accumulated errors and gradually decrease the accuracy under the long term measurement, and the traditional unitary estimation method makes the prediction of the state of charge (SOC) misaligned and indirectly affects the related functions of the battery protection. For example, in order to calculate the SOC, the Coulomb counting method is generally used, that is, the charge and discharge current is integrated with time and then the dynamic SOC of the battery could be estimated. However, this method requires high accuracy of the current measurement, and accumulated errors are easily caused by inaccurate calculations of the residual SOC under the long term calculation. 
     SUMMARY 
     To solve the aforesaid questions, one aspect of the present disclosure is to provide a type of the battery controller, coupled between a battery module and a charge and discharge circuit. The battery controller includes an auxiliary measurement energy-storing component, a control unit, a measuring unit and a protection unit. 
     The battery controller of the present disclosure includes an auxiliary measurement energy-storing component, a control unit, a measuring unit and a protection unit. The control unit is coupled to the auxiliary measurement energy-storing component and the measuring unit respectively. The auxiliary measurement energy-storing component is coupled to the battery module, the measuring unit and the control unit. The auxiliary measurement energy-storing component is coupled in series to the battery module relatively to the charge and discharge circuit. The measuring unit is coupled in series to the battery module relatively to the charge and discharge circuit, and the measuring unit is coupled to the control unit. The protection circuit is coupled to the battery module and the charge and discharge circuit, to limit the current value to be not greater than a predetermined value. 
     In the present disclosure, the battery module includes at least two lithium batteries and has a first discharge curve. 
     In the present disclosure, the auxiliary measurement energy-storing component is a lithium battery having a second discharge curve different from the first discharge curve of the battery module. 
     In the present disclosure, the battery module is charged and discharged through the charge and discharge circuit, the measuring unit measures a current value of current flowing through the battery module and provides the current value to the control unit. The control unit calculates a first SOC value according to the current value. 
     In the present disclosure, when the battery module is in a static condition, the auxiliary measurement energy-storing component provides an open-circuited voltage to the control unit. The control unit generates a second SOC value according to the open-circuited voltage. The second SOC value is configured to modify or replace the first SOC value. 
     In this disclosure, the protection circuit is a relay or fuse. 
     The other aspect of the present disclosure provides a type of battery level measurement method, including the following operations: 
     1. Determines whether the battery module is in the static condition.
 
2a. In response to that the battery module not be in a static condition and then performs the following operations: the measuring unit measures the current value of the current through the battery module, the control unit utilizes the Coulomb counting method to calculate and output the first SOC value according to the current value.
 
2b. In response to that the battery module be in a static condition and then performs the following operations: the auxiliary measurement energy-storing component provides the open-circuited voltage to the control unit. The control unit generates the second SOC value according to the open-circuited voltage and SOC data. The second SOC value is configured to modify or replace the first SOC value.
 
     In summary, the embodiment of the present disclosure utilizes the auxiliary measurement energy-storing component connected in series to the battery module to be measured, and the residual SOC of the battery to be measured can be modified according to the open-circuited voltage of the auxiliary measurement energy-storing component in response to the battery as in a static condition, which can avoids the inaccuracy caused by accumulated errors of the traditional method and estimates the residual SOC accurately. 
     It is to be understood that both the foregoing general description and the following detailed description are by examples and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be more fully understood by reading the following detailed description of the embodiment with reference to the accompanying drawings as follows. 
         FIG. 1A  is a schematic diagram of a battery control system in accordance with one embodiment of the present disclosure. 
         FIG. 1B  is a schematic diagram of a battery control system in accordance with one embodiment of the present disclosure. 
         FIG. 1C  is a schematic diagram of a control unit in accordance with one embodiment of the present disclosure. 
         FIG. 2A  is a schematic diagram of a first discharge curve of the battery module in accordance with one embodiment of the present disclosure. 
         FIG. 2B  is a schematic diagram of a second discharge curve of the auxiliary measurement energy-storing component in accordance with one embodiment of the present disclosure. 
         FIG. 3  is a schematic diagram of a discharge curve of the operation flowchart of the measurement method in accordance with one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
     The following embodiments are disclosed with accompanying diagrams for detailed description. For illustration clarity, many details of practice are explained in the following descriptions. However, it should be understood that these details of practice do not intend to limit the present disclosure, and descriptions of structure operation do not intend to limit the order of execution, any structure that reassembles the components to produce a device with equal efficacy is within the scope of the present invention. In addition, the illustrations are for illustration purposes only and are not drawn to full size. In order to facilitate understanding, the same elements in the following description will be described with the same symbols. 
     The terms used throughout the specification and the scope of patent applications, unless otherwise specified, they usually have the ordinary meaning of each term used in this field, in the content disclosed here and in special content. Certain terms used to describe this disclosure are discussed below or elsewhere in this specification to provide an additional guidance to those skilled in the art on the description of this disclosure. 
     It will be understood that, although the terms of first, second, third etc., may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present disclosure. 
     In the description herein and throughout the claims that follow, the terms “comprise” or “comprising,” “include” or “including,” “have” or “having,” “contain” or “containing” and the like used herein are to be understood to be open-ended, i.e., to mean including but not limited to. 
     In this document, the term “coupled” may also be termed as “electrically coupled,” and the term “connected” may be termed as “electrically connected.” “Coupled” and “connected” may mean “directly coupled” and “directly connected” respectively, or “indirectly coupled” and “indirectly connected” respectively. “Coupled” and “connected” may also be used to indicate that two or more elements cooperate or interact with each other. 
     Several embodiments of this disclosure will be disclosed graphically below. For clarity, many practical details will be explained in the following description. However, it should be understood that these practical details should not be applied to limit the disclosure. That is, in some embodiments of this disclosure, these practical details are unnecessary. In addition, in order to simplify the drawings, some conventional structures and elements will be shown in the drawings in a simple and schematic manner. 
       FIG. 1A  is a schematic diagram illustrating a type of a battery control system  100 A in accordance with one of the embodiment of the present disclosure. Referring to  FIG. 1A , the battery control system  100 A includes a battery controller  105 A, wherein the battery controller is configured to be coupled between a battery module  110  and a charge and discharge circuit  115 . In the embodiment of the present disclosure, the battery controller  105 A includes an auxiliary measurement energy-storing component  120 , a control unit  130 , a measuring unit  140  and a protection unit  150 . The auxiliary measurement energy-storing component  120  is coupled to the battery module  110  and the measuring unit  140 . The auxiliary measurement energy-storing component  120  is also coupled to the control unit  130 . The auxiliary measurement energy-storing component  120  is coupled in series to the battery module  110  relatively to the charge and discharge circuit  115 . The measuring unit  140  is coupled in series to the battery module  110  relatively to the charge and discharge circuit  115 . The measuring unit  140  is coupled to the control unit  130 , and the measuring unit  140  is configured to measure a current value of current flowing through the battery module  110  and transmit a measured result to the control unit  130 . The protection unit  150  is coupled between the battery module  110  and the charge and discharge circuit  115 , and further coupled to the measuring unit  140  and the auxiliary measurement energy-storing component  120 . 
     As the embodiment shown in  FIG. 1A , the battery module  110  is coupled in series to the auxiliary measurement energy-storing component  120  and the measuring unit  140  relatively to the charge and discharge circuit  115 , and the auxiliary measurement energy-storing component  120  is located between the battery module  110  and the measuring unit  140 . 
     Referring to  FIG. 1A , the battery module  110  includes at least one battery (not shown), and a state of charge (SOC) of battery module  110  has the corresponding changes in response to that the battery module  110  is charged or discharged. 
     In the present disclosure, the battery module  110  includes at least one lithium battery. The at least one lithium battery of the battery module  110  is connected in serial or parallel to each other according to the consideration of outputting the voltage or the current. 
     Reference is made to  FIG. 2A ,  FIG. 2A  is a first discharge curve of the battery module  110  of the present embodiment. That is, the two-dimensional schematic diagram is the open-circuited voltage OV of the battery module  110  relatively to the SOC. Referring to  FIG. 2A , vertical axis unit is voltage (V), horizontal axis unit is milliamp hours (mAh). In some embodiments, the curve of  FIG. 2A  illustrates the change between the aforesaid open-circuited voltage OV and the SOC of the battery module  110 . Wherein the aforesaid voltage of the battery module may be expressed as the first SOC value SOC 1 . 
     Furthermore, the change of voltage relatively to the change of battery capacity (mAh) of the battery module  110  is not obviously in response to that the battery module  110  is discharged for a long term. That is, the slope of the first discharge curve is small, thus the errors are easily caused while estimating the SOC. 
     Reference is also made to  FIG. 2B ,  FIG. 2B  is a second discharge curve of the auxiliary measurement energy-storing component  120  in accordance with the present embodiment. Different from  FIG. 2A , in response to that the auxiliary measurement energy-storing component  120  is discharged for the long term, the change of the voltage relatively to the change of the battery capacity (mAh) in the second discharge curve is obviously. That is, the slope of the second discharge curve is large, thus the errors are not easily caused while estimating the SOC. 
     In response to that the battery module  110  is coupled in series to the auxiliary measurement energy-storing component  120 , while the battery module  110  and the auxiliary measurement energy-storing component  120  are discharging, both of them have the same decreasing ratio of the SOC. In the case of the battery module  110  coupled in series to the auxiliary measurement energy-storing component  120 , the auxiliary measurement energy-storing component  120  is also configured to provide the corresponding open-circuited voltage OV. 
     In the present embodiment, the composition of the lithium battery of the auxiliary measurement energy-storing component  120  is different from that of the at least one of the lithium batteries of the battery module  110 , and both of they have the different discharge curves. 
     In the present embodiment, the auxiliary measurement energy-storing component  120  may be following constituent components, but not in the limit: a lithium cobalt oxide battery (LiCoO 2 ), lithium manganese oxide battery (LiMn 2 O 4 ), lithium nickel oxide battery (LiNiO 2 ), lithium nickel manganese oxide battery (Li(Ni x Co y Mn z )O 2 ), electric double-layer capacitor (electric double layer capacitor) or combinations thereof. 
     In some embodiments, a maximum value of the capacity of the battery module  110  is equal to or less than a maximum value of the capacity of the auxiliary measurement energy-storing component  120 . In other words, the maximum first SOC value SOC 1  of the battery module  110  is not greater than the maximum second SOC value SOC 2  of the auxiliary measurement energy-storing component  120 . 
     As the embodiment shown in  FIG. 1A , the control unit  130  is coupled to the auxiliary measurement energy-storing component  120 , configured to measure the open-circuited voltage OV of the auxiliary measurement energy-storing component  120 , and the open-circuited voltage OV is utilized to estimate the second SOC value SOC 2  of the auxiliary measurement energy-storing component  120  by using lookup table. In some embodiments, the auxiliary measurement energy-storing component  120  can be operated as the specific energy-storing component of the main circuit of the battery controller  105 A connected in series, and is configured to be operated as an aligned element to estimate the residual SOC of the battery control system  100 A. As the aforementioned, the open-circuited voltage OV of the auxiliary measurement energy-storage component  120  and the second SOC value SOC 2  have an obvious identifiability of the slope. Therefore, in some embodiments, the two-dimension curve and the slope of the open-circuited voltage OV of the auxiliary measurement energy-storing component  120  versus the second SOC value SOC 2  can be recorded as the SOC data D which can be stored in the memory (such as the memory as shown in  FIG. 1C ) so that the first SOC value SOC 1  of the battery module  110  can be calculated by measuring the open-circuited voltage OV of the auxiliary measurement energy-storing component  120  and performing the lookup table estimation with the SOC data D stored in the memory. In some embodiments, the control unit  130  may further calculates the second SOC value SOC 2  according to the lookup table, such that the first SOC value SOC 1  can be estimated, and the current residual SOC of the battery module  110  can be accurately estimated without generating accumulated errors. 
     In some embodiments, the control unit  130  calculates the current power consumption of the auxiliary measurement energy-storing component  120  according to the maximum SOC value of the auxiliary measurement energy-storing component  120  and the current second SOC value SOC 2 . And then the control unit  130  calculates the residual SOC of battery module  110  according to the SOC of the power consumption of the auxiliary measurement energy-storing component  120  and the maximum SOC value of the battery module  110 . In some embodiments, the battery module  110  is coupled in series to the auxiliary measurement energy-storing component  120 . Therefore, the value of current flowing through the battery module  110  will be same as the current of the auxiliary measurement energy-storing component  120 , the battery module  110  and the auxiliary measurement energy-storing will have the same power consumption at the same time. 
     As the embodiments shown in  FIG. 1A , the measuring unit  140  is coupled to the control unit  130  and the auxiliary measurement energy-storing component  120 , and is configured to measure the current flowing through the auxiliary measurement energy-storing component  120  for calculating the residual SOC by the control unit  130 . In some embodiments, the measuring unit  140  is implemented with the current sensor or the other suitable current sensing element, but the disclosure should not be limited by these terms. 
     The protection unit  150  is coupled to the measuring unit  140  and the battery module  110 , and is configured to limit the aforesaid current value to be not greater than the predetermined value to keep the battery controller  105 A in safe. In some embodiments, the protection unit  150  is implemented with the over current protection, the relay, the fuse or other similar elements, but the disclosure should not be limited by these terms. The protection unit  150  turns off the circuit or sends out the warning to alert the user in response to that the value of current flowing through the battery controller  105 A exceeds the aforesaid predetermined value. 
     Reference is made to  FIG. 1B .  FIG. 1B  is a schematic diagram of the battery control system  100 B in accordance with other embodiments of the disclosure. The battery control system  100 B shown in  FIG. 1B  is similar to the battery control system  100 A shown in  FIG. 1A . The difference is that the auxiliary measurement energy-storing component  120  shown in  FIG. 1B  is not coupled in series to the measuring unit  140 . Furthermore, the auxiliary measurement energy-storing component  120  and the measuring unit  140  are respectively disposed on different current paths coupled to the battery module  110 , and the auxiliary measurement energy-storing component  120  and the measuring unit  140  are coupled between the battery module  110  and the protection unit  150 . 
     As the embodiment shown in  FIG. 1B , the measuring unit  140  is coupled to the control unit  130  and the battery module  110 , and is configured to measure the current value of the current flowing through the battery module  110  for calculating the residual SOC by the control unit  130 . In some embodiments, the measuring unit  140  is implemented with the current sensor or the other suitable current sensing element, but the disclosure should not be limited by these terms. In some embodiments, the function of the individual element or the unit of the battery control system  100 B are similar to the corresponding function of the individual element or the unit of the battery control system  100 A, so no more tautology here. 
     Reference is made to  FIG. 1C .  FIG. 1C  is a schematic diagram of the control unit  130  in accordance with some embodiments of the present disclosure. Referring to  FIG. 1C , the control unit  130  includes the memory  170 , the processor  180  and the display unit  190 , wherein the display unit  190  is coupled between the memory  170  and the display unit  190 . 
     The memory  170  is configured to store the SOC data D related to the auxiliary measurement energy-storing component  120 . In some embodiments, the SOC data D is a ratio constituted by both the open-circuited voltage OV of the auxiliary measurement energy-storing component  120  and the SOC. In other words, the SOC data D is constituted by both the open-circuited voltage OV and the SOC, and the value of these two parameters could be drawn as a curve in the two dimensional coordinate plane (as shown in  FIG. 2B ). Consequently, the change of the slope can be recorded. 
     In some embodiments, the memory  170  is implemented with non-transitory computer-readable medium. In some embodiments, the computer readable mediums can be the electrical, magnetic, optical, infrared and/or semiconductor system (or the equipment or device.) Such as, the computer-readable medium includes the semiconductor or the solid-state memory, the magnetic tape, the removable computer disk, the random access memory (RAM), the read-only memory (ROM), hard disk and/or optical disk. In one or multiple embodiments of using the optical disk, the computer readable medium includes compact read-only memory disc (CD-ROM), compact rewritable disc (CD-R/W) and/or digital video disc (DVD). 
     The processor  180  is configured to determine the condition of battery module  110  according to the current measured by the measuring unit  140 . In response to that the current value is not equal to zero, the processor  180  determines the battery module  110  as in a dynamic condition, this represents the battery module  110  is supplying with the power. Meanwhile, the processor  180  utilizes the Coulomb counting method to calculate the present residual SOC of the battery module  110  according to the current value, and outputs the first SOC value SOC 1  of the battery module  110  to the display unit  190 . 
     In response to that the current value is equal to zero, the processor  180  determines the battery module  110  as in a static condition, which represents the battery module  110  be in an idle state and does not supply the power. Meanwhile, processor  180  measures the open-circuited voltage OV of the auxiliary measurement energy-storing component  120  and performs the lookup table operations with the SOC data D stored in the memory to estimate the present residual SOC of the auxiliary measurement energy-storing component  120 , and the estimated value is marked as the second SOC value SOC 2 . 
     In some embodiments, the Coulomb counting method also known as current integration method, which is performed the current value-time integration via the current value measured directly by the control unit  130  to calculate the value of SOC. The Coulomb counting method is an intuitive way to estimate the values of SOC, and it may calculate the consumed or replenished power to estimate the residual SOC of the battery. 
     In some embodiments, the processor  180  is further configured to estimate the first SOC value SOC 1  of the battery module  110  according to the second SOC value SOC 2  of the auxiliary measurement energy-storing component  120  and output the first SOC value SOC 1  of the battery module  110  as a battery level, and the battery level is transmitted to the display unit  190 , such that the display unit  190  can display the battery level. 
     In each of the embodiments of the present disclosure, the processor  180  can be implemented by the central processing unit, application-specific integrated circuit, the multiprocessor, the decentralized processing system or the suitable processing circuit, these elements should not be limited by these terms. 
     In some embodiments, the display unit  190  can be implemented by a display device, configured to display images and data, the element should not be limited by these terms. In some embodiments, the display unit  190  can be implemented by various screens, the control unit  130  controls screens to display a picture, the picture may include multiple layers, wherein these layers is configured to display different applications, a graphical user interface, a system status bar, a task bar, etc. In some other embodiment, the control unit  130  can further includes a graphics card (not shown) or a video processing circuit (not shown) and other circuit components. The circuit elements of above mention can be controlled by the processor  180 , in order to provide a processed image data to the display unit  190  to display. 
     The aforesaid structure of the control unit  130  is illustration purposes only, but the present disclosure is not limited thereto. The structure of control unit  130  of the present disclosure can be changed and adjusted without departing from the scope or spirit of the disclosure. For example, in different embodiments, the control unit  130  can be implemented by a central processing unit, microprocessor or the other suitable processor directly, without the aforesaid display unit  190  and/or the memory  170 . 
       FIG. 3  is an operation flowchart illustrating measurement method  300  in accordance with some embodiments of the present disclosure. Referring to  FIG. 3 , the measurement method  300  determines the current usage status of the battery by detecting the whole battery loop current and cooperating with a lookup table and the Coulomb counting method to correct the estimate accuracy of the residual SOC. The below mentioned measurement method  300  with the battery controller  105 B shown in  FIG. 1B  are the illustrations, and the measurement method  300  is not limited to the application of the battery controller  105 B as shown in  FIG. 1B , that is the measurement method  300  can be applied in any similar circuit. 
     In the operation S 310 , the control unit  130  determines whether the battery module  110  is in a static condition. In other words, the control unit  130  determines the operating mode of the battery module  110  according to the current value. If the measured current value is equal to zero, the battery  110  is determined as in a static condition and the operation S 320  is performed. If the measured current value is not equal to zero, the battery  110  is determined as a dynamic condition. And then, the operation S 321  is performed. 
     In the operation S 320 , the control unit  130  generates the second SOC value SOC 2  according to the open-circuited voltage OV and the SOC data D. Specially, the control unit  130  compares the SOC data D stored in memory  170  according to the open-circuited voltage OV of the auxiliary measurement energy-storing component  120 , in order to generate the second SOC value SOC 2 . 
     In the operation S 330 , the control unit  130  modifies or replaces the first SOC value SOC 1  according to the second SOC value SOC 2 . Specially, the control unit  130  estimates the first SOC value SOC 1  according to the second SOC value SOC 2  and modifies or replaces the first SOC value SOC 1  in response to the second SOC value SOC 2  is different from the first SOC value SOC 1 . In other words, the second SOC value SOC 2  of the auxiliary measurement energy-storing component  120  will be in contrast with the first SOC value SOC 1  of the battery module  110  by the control unit  130 , the control unit  130  outputs the second SOC value SOC 2  to replace the first SOC value SOC 1  in response to that the second SOC value SOC 2  is not equal to the first SOC value SOC 1 . On the other hand, the control unit  130  outputs the second SOC value SOC 2  will be substantially the same as the first SOC value SOC 1  of the battery module  110  in response to that the second SOC value SOC 2  is equal to the first SOC value SOC 1  without affecting the original circuit operation. 
     Back to the operation S 310 , the battery module  110  be in a dynamic condition since the current value is not zero, meanwhile the operation S 321  is continuously performed by the measuring unit  140  to measure the current value of the current flowing through the battery module  110 . 
     Then, in the operation S 322 , the control unit  130  calculates the first SOC value SOC 1  according to current value by utilizing the Coulomb counting method and outputs the first SOC value SOC 1 . Specially, the control unit  130  calculates the first SOC value SOC 1  of the battery module  110  according to current value by utilizing the Coulomb counting method, and outputs the first SOC value SOC 1 . 
     In the aforesaid operation, in response to that the control unit  130  determines the battery module  110  as in a dynamic condition, the control unit  130  can perform the Coulomb counting method with the current value measured by the measuring unit  140  to calculate the residual SOC of the battery module  110 . On the other hand, in response to that the control unit  130  determines the battery module as in a static condition, the control unit  130  measures the open-circuited voltage OV of the auxiliary measurement energy-storing component  120  and contrasts the open-circuited voltage OV with the SOC data D stored in the memory  170  in order to further calculate the residual SOC of the battery module  110 . Therefore, the battery module  110  can utilizes different residual SOC estimation methods for different conditions according to the measurement method  300 , in order to correct the accumulated errors generated by utilizing only the Coulomb counting method. 
     The aforesaid descriptions of the operations S 310  to S 340  may refer to previous figures of the embodiments, so no more tautology here. The multiple operations of aforesaid multiple operations of the measurement method  300  are examples only and are not limited to the sequential execution of the above examples. Without departing from the operation mode and scope of the embodiments of the present invention, various operations under the measurement method  300  can be appropriately added, replaced, omitted, or performed in different orders. 
     In summary, the embodiment of the disclosure is an auxiliary measurement energy-storing component coupled in series to the battery to be measured, and estimating the residual SOC of the battery to be measured according to the open-circuited voltage of the auxiliary measurement energy-storing component in response to that the battery be in a static condition, which can avoid the inaccuracy caused by the accumulated errors of the traditional method and prevent the battery damage caused by the overcharge or discharge and estimates residual SOC accurately, in order to improve user experience. 
     Although the disclosure has been disclosed as above in the implementation mode, it is not limited to this disclosure. Anyone who is familiar with this skill can make various modifications and retouches without departing from the spirit and scope of this case. Therefore, the scope of protection in this disclosure shall be determined by the scope of the attached patent application.