Patent Publication Number: US-2021181258-A1

Title: Battery pack diagnostic method and battery pack diagnostic device

Description:
CROSS-REFERENCE TO RELATED INVENTIONS 
     This invention claims the priority of CN application Serial No. 201911301100.7, filed on Dec. 17, 2019, the disclosures of which are hereby incorporated by reference in their entirety. 
     TECHNICAL FIELD 
     The present invention relates to a battery pack diagnostic method and a battery pack diagnostic device using the battery pack diagnostic method. 
     BACKGROUND ART 
     At present, lithium battery packs have been widely used in various power tools as a power source. However, the battery pack is due to charged and discharged frequently and working under great intensity, and the limitations of the battery pack&#39;s own volume, operating conditions, manufacturing cost and other factors, the battery pack is prone to be damaged, and the fault location is difficult to judged and so on. Once a fault occurs, it is difficult for users to troubleshoot the failure, and more often seek help from the seller or maintenance service site. However, the professional knowledge of the sellers and maintenance service site staff is limited. They usually transfer the repair pressure to the equipment manufacturer, such as returning to the factory for servicing. If only for some minor reasons or some simple component failures, the product is sent back to the factory for repair, it will not only increase the maintenance cost, but also make the user wait a long time, thereby reducing the user&#39;s experience. 
     Secondly, after the battery pack fails, the current commonly used judging method is to use a matching charger and discharging tool to charge and discharge the battery pack for a short period of time, so as to carry out a rough qualitative by the failure phenomenon of the battery pack during the charging and discharging process. Then, disassemble the battery pack for further analysis. Although this method of operation is simple, it has some drawbacks. First of all, this method has detection limitations. Some faults cannot be seen by a short-time charging and discharging, e.g. charging MOS drain-source short-circuited. Secondly, this method cannot accurately locate the fault location, for example, when the matching charger is abnormally charged, the fault location cannot be determined. Finally, the diagnostic efficiency of this method is relatively low, which even needs maintenance personnel to charge and discharge multiple times to determine the fault type and fault location of the battery pack, which seriously reduces the work efficiency of the maintenance personnel. 
     In view of the above, It is necessary to provide a battery pack diagnostic method and a battery pack diagnosis device using the battery pack diagnostic method to solve the above problems. 
     SUMMARY OF INVENTION 
     The objective of the present invention is to provide a battery pack diagnostic method and a battery pack diagnostic device using the battery pack diagnostic method. The battery pack diagnostic method could detect the battery pack quickly and comprehensively, and locate the fault accurately which improves the work efficiency of the maintenance personnel. 
     In order to achieve the object, the present invention provides a battery diagnostic method, which is implemented to diagnose the battery pack when the battery pack is inserted into the battery pack diagnostic device, the method comprises following steps: 
     detecting a battery temperature and an ambient temperature of the battery pack; if the difference between the two temperatures is less than a preset temperature threshold, the state of temperature of the battery pack is instructed as normal, if not, the state of temperature of the battery pack is instructed as abnormal; 
     detecting a pre-load voltage of a discharge port of the battery pack before loading and a post-load voltage after loading; if the difference between the two voltages is less than a preset voltage threshold, the state of discharging circuit of the battery pack is instructed as normal, if not, the state of discharging circuit of the battery pack is instructed as abnormal; 
     detecting a charge voltage of a charge port of the battery pack and a discharge voltage of the discharge port; if the two voltages are equal, the state of charging circuit of the battery pack is instructed as normal, if not, the state of charging circuit of the battery pack is instructed as abnormal; 
     detecting whether a hot-plugging interface of the battery pack has a hot-plugging signal; if the hot-plugging interface of the battery pack has the hot-plugging signal, the state of hot-plugging interface of the battery pack is instructed as normal, if not, the state of hot-plugging interface of the battery pack is instructed as abnormal. 
     As a further improvement of the invention, wherein further comprises: detecting whether a charging MOS tube could be turned off when detecting the charge voltage of the charge port of the battery pack and the discharge voltage of the discharge port; if the charging MOS tube could be turned off and the two voltages are equal, the state of charging circuit of the battery pack is instructed as normal, if not, the state of charging circuit of the battery pack is instructed as abnormal. 
     As a further improvement of the invention, further comprises: determining whether the battery pack has been working for a preset time; if so, detecting the battery temperature of the battery pack before detecting the battery temperature and the ambient temperature of the battery pack, if not, detecting the battery temperature of the battery pack after the battery pack has been working for the preset time. 
     As a further improvement of the invention, the battery diagnostic method further comprises a step S 5 : storing the temperature detection information, the discharging circuit detection information, the charging circuit detection information, and the hot-plugging interface detection information. 
     As a further improvement of the invention, the preset temperature threshold is 1° C., 3° C., 5° C., 7° C. or 9° C., preferably 3° C. 
     As a further improvement of the invention, the preset voltage threshold is 0.5V, 1V, 1.5V, 2V, 2.5V or 3V, preferably 1V. 
     As a further improvement of the invention, the preset time is 10 min, 15 min, 20 min or 30 min, preferably 15 min. 
     In order to achieve the object, the present invention also provides a battery pack diagnostic device comprising: a temperature detection module comprising an information acquisition circuit for reading a battery temperature information of the battery pack and a temperature detection circuit for detecting an ambient temperature; a discharge detection module comprising a discharge loading circuit for providing a load to a discharge port and a discharge port voltage sampling circuit; a charge detection module comprising a charge voltage sampling circuit; 
     a hot-plugging detection module comprising a hot-plugging detection circuit for detecting whether a hot-plugging port has a hot-plugging signal; and 
     a controlling module to control the temperature detection module, the discharge detection module, a charge detection module and a hot-plug detection module, to detect whether the battery pack is normal through the battery pack diagnostic method. 
     As a further improvement of the invention, the battery pack diagnostic device further comprises a communicating module for communication with an external equipment. 
     As a further improvement of the invention, the communication module is WLAN module, Blue Tooth module, 5G communication module, infrared communication module or USB interface. 
     As a further improvement of the invention, the battery pack diagnostic device further comprises a storage module for storing diagnostic informations. 
     As a further improvement of the invention, Q 5  and Q 4  are MOS tubes in the discharge loading circuit which is used as switches in the circuit in order to load the battery discharge port voltage P+ to the resistors RA 1  and RA 9  for discharge; U 1 A, U 1 B and U 1 C are all Operation Amplifier, R 38  and R 39  are voltage sampling divider resistors, U 1 C acts as voltage signal isolation to protect the MCU voltage sampling port. 
     As a further improvement of the invention, DA 1  (BAT 54 S) in the hot-plug detection circuit is a protective diode used for absorbing the instantaneous large positive and negative voltages on the J 5 -PIN 1  foot and protecting the MOS tube QA 1 . 
     The beneficial effects of the present invention are: the battery pack diagnostic method and the battery pack diagnostic device using the battery pack diagnostic method can quickly and comprehensively detect the battery pack and accurately determine the fault location, which improve working efficiency of the maintenance personnel. 
     The above general description and the following detailed description are intended to be illustrative and not restrictive. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic process diagram of a battery pack diagnostic method of the present invention. 
         FIG. 2  is a schematic module diagram of a battery pack diagnosis device of the present invention. 
         FIG. 3  is a schematic diagram showing a discharge port voltage sampling circuit and a charge port voltage sampling circuit. 
         FIG. 4  is a schematic diagram of a discharge and loading circuit. 
         FIG. 5  is a schematic diagram of a hot-plugging detection circuit. 
         FIG. 6  is a schematic diagram of a USB communication circuit. 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     The exemplary embodiment will be described in detail herein, and the embodiment is illustrated in the accompanying drawings. 
     Referring to  FIG. 1 , the present invention discloses a battery pack diagnostic method. After the battery pack connects to the battery pack diagnostic instrument, the battery pack implements the above diagnosis method and diagnoses the battery pack. The battery pack diagnostic method includes the following steps without particular order: 
     S 1 : detecting a battery temperature and an ambient temperature of the battery pack; if the difference between the two temperatures is less than a preset temperature threshold, the state of temperature of the battery pack is instructed as normal, if not, the state of temperature of the battery pack is instructed as abnormal. 
     The battery temperature refers to the temperature of the battery of the battery pack, and the ambient temperature refers to the temperature of the environment where the battery pack is located. The battery temperature and the ambient temperature can be measured by a temperature detection circuit composed of a temperature sensor. The preset temperature threshold can also be set by the factory or the maintenance personnel according to specific situation, e.g. 1° C., 3° C., 5° C., 7° C. or 9° C. In the present embodiment, the preset temperature threshold is 3° C. 
     Preferably, the step S 1  may further include step S 11 : determining whether the battery pack has been working for a preset time; if so, detecting the battery temperature of the battery pack, otherwise, otherwise detecting the battery temperature of the battery pack after the battery pack has been working for a preset time. This arrangement makes the battery pack have sufficient working time, so that the abnormal temperature problem of the battery pack can be fully reflected, and avoid the abnormal temperature problem of the battery pack from being covered up due to the insufficient working time of the battery pack, thereby effectively improve the accuracy of battery pack diagnosis. The preset time may be preset by the factory and may also be preset by the maintenance personnel according to specific situation. In this embodiment, the preset time might be 10 min, 15 min, 20 min or 30 min, in which 15 min is preferable choice. 
     S 2 : detecting a pre-load voltage of a discharge port of the battery pack before loading and a post-load voltage after loading; if the difference between the two voltages is less than a preset voltage threshold, the state of discharging circuit of the battery pack is instructed as normal, if not, the state of discharging circuit of the battery pack is instructed as abnormal; 
     The pre-load voltage refers to the voltage of the discharge port of the battery pack before loading and the post-load voltage refers to the voltage of the discharge port of the battery pack after loading. The pre-load voltage and the post-load voltage may be measured by the discharge port voltage sampling circuit located at the discharge port. The preset voltage threshold may be set by the factory or the maintenance personnel according to the specific situation. In the present embodiment, the preset voltage threshold is preferably 0.5V, 1V, 1.5V, 2V, 2.5V or 3V, more preferably 1V. 
     S 3 : detecting a charge voltage of a battery pack charge port and the discharge voltage of the discharge port; if the two voltages are equal, the state of charging circuit of the battery pack is instructed as normal, if not, the state of charging circuit of the battery pack is instructed as abnormal; 
     The charge voltage refers to the voltage of the charge port of battery pack during charging and the discharge voltage refers to the voltage of the discharge port of the battery pack during discharging. The charge voltage may be measured by the charge port voltage sampling circuit set at the charge port, and the discharge voltage may be measured by the discharge port voltage sampling circuit set at the discharge port. The present embodiment judges whether the charging circuit of the battery pack is normal by judging whether the charge voltage and the discharge voltage are equal. However, in other embodiments, it is also possible to judge whether the charging circuit of the battery pack is normal by judging whether the difference between the charging voltage and the discharging voltage is less than a preset threshold. The preset threshold may be preset by the factory or set by the maintenance personnel according to the specific situation. As can be understood, the aforementioned two schemes can also coexist and be chosen by the maintenance personnel on a case-by-case basis. 
     Preferably, the step S 3  also includes step S 31 : detecting whether a charging MOS tube could be turned off; if the charging MOS tube could be turned off and the two voltages are equal, the state of charging circuit of the battery pack is instructed as normal, if not, the state of charging circuit of the battery pack is instructed as abnormal. 
     S 4 : detecting whether a hot-plugging interface of the battery pack has a hot-plugging signal; if the hot-plugging interface of the battery pack has the hot-plugging signal, the state of hot-plugging interface of the battery pack is instructed as normal, if not, the state of hot-plugging interface of the battery pack is instructed as abnormal. 
     S 5 : storing the temperature detection information, the discharging circuit detection information, the charging circuit detection information, and the hot-plugging interface detection information. 
     The temperature detection information, the discharging circuit detection information, the charging circuit detection information, and the hot-plugging interface detection information could be stored in the battery pack diagnosis device and could be also stored in an external equipment connected with the battery pack diagnosis device. The external equipment could be a computer, a tablet computer and so on. The abnormal information of the battery pack can be displayed on the display screen, can also be displayed by the fault indicator, and can also indicate the fault type, location and other information through voice prompts. 
     Referring to  FIG. 2 , the present invention also discloses a battery pack diagnostic device  100  comprising a temperature detection module  10 , a discharge detection module  20 , a charge detection module  30 , a hot-plugging detection module  40 , a communication module  50 , a storage module  60  and a controlling module  70 . 
     Referring to  FIG. 2 , the temperature detection module  10  includes an information acquisition module  11  and a temperature detection circuit  12 . The information acquisition circuit  11  reads the temperature information of the battery pack through a signal terminal provided on the battery pack. In this embodiment, the battery temperature is obtained by reading the characteristic data of the battery pack by the information acquisition circuit  11 . However, in other embodiments, an additional battery temperature detection circuit can also be provided to directly detect the temperature of the cells in the battery pack. The temperature detection circuit  12  is used to detect the ambient temperature of the environment where the battery pack is located. The discharge detection module  20  includes a discharge loading circuit  21  and a discharge port voltage sampling circuit  22 . The discharge loading circuit  21  is used to provide a load for the discharge port of the battery pack, and its specific structure is shown in  FIG. 4 . The discharge port voltage sampling circuit  22  is used to detect the pre-load voltage before the discharge port is loaded and the post-load voltage after the load. The charge detection module  30  includes a charge port voltage sampling circuit for detecting the voltage of the charge port. The discharge port voltage sampling circuit  22  and the charge port voltage sampling circuit are shown in  FIG. 3 . The hot-plugging detection module  40  includes a hot-plugging detection circuit for detecting whether the hot-plugging interface provided on the battery pack has a hot-plugging signal. The specific structure of the hot-plugging detection circuit is shown in  FIG. 5 . The storage module  60  is used to store diagnostic information to facilitate maintenance personnel to use in the future and quickly locate the fault location during maintenance. The communication module  50  is used to enable the battery pack diagnostic device  100  to communicate with external devices (for example, a computer, a tablet computer, etc.). The communication module  50  may be a wired communication module or a wireless communication module. The wired communication module may be a USB interface, and the wireless communication module may be a WLAN module, a Bluetooth module, a 5G communication module, an infrared communication module and so on. The present invention does not make specific restrictions on this. The controlling module  70  controls the operations of the temperature detection module  10 , the discharge detection module  20 , the charge detection module  30 , and the hot-plugging detection module  40 , and determines whether the battery pack is abnormal by the aforementioned battery pack diagnostic method. The controlling module  70  may be a chip processor, for example: an MCU processor. Analysis software can be run on the external equipment, and the user imports the diagnostic data of the battery pack into the external equipment, so as to obtain a comprehensive diagnostic result of the battery pack through the analysis software, and an electronic analysis report or a printed paper report can be sent to the user. 
     Referring to  FIG. 3  and  FIGS. 4 , Q 5  and Q 4  are MOS tubes, which act as switches in the circuit in order to load the battery discharge port voltage P+ to the resistors RA 1  and RA 9  for discharge; U 1 A, U 1 B and U 1 C are all Operation Amplifier, R 38  and R 39  are voltage sampling divider resistors, U 1 C acts as voltage signal isolation to protect the MCU voltage sampling port; the discharge loading circuit works as follows: MCU makes the battery discharge terminal (DISCh) generate a signal, at this time Q 5  and Q 4  is turned on, the discharge port voltage P+ is divided by the resistors R 38  and R 39  and then applied to the MCU&#39;s voltage sampling terminal (DisCharging Function), and then the value of the discharge port voltage P+ is read. 
     The discharge port and the charge port voltage sampling circuit modules work as follows: the battery discharge port voltage P+ is divided by the resistors R 29  and R 34 , and then isolated by the U 1 A operation amplifier, and then added to the OCV voltage sampling port of the MCU for voltage sampling processing. The battery charge port voltage C+ is divided by the resistors R 28  and R 33 , and then transmitted and isolated by the U 1 B, which is finally added to the ChV voltage sampling port of the MCU for voltage sampling processing. 
     As shown in  FIG. 5 , DA 1  (BAT 54 S) is a protective diode used to absorb the instantaneous large positive and negative voltages on the J 5 -PIN 1  foot, and protect the MOS tube QA 1  and J 5  from an external hot-plug switch. When the hot-plug switch is disconnected, QA 1  is off, and the voltage of the MCU&#39;s Battery_PlugIn_Detect voltage sampling port is 0V. When hot-plug switch is connected, Pin 1  and Pin 2  of J 5  are shorted. At this time, 5VD is divided by RA 30  and RA 29  to make the GS voltage of MOS tube QA 1  greater than the threshold, and then QA 1  is turned on. At this time, the voltage of the Battery_PlugIn_Detect voltage sampling port of the MCU is 5V. 
     As shown in  FIG. 6 , the present embodiment uses a USB module as the communication module, uses U 2  (CP 2102 ) as a USB-to-serial signal conversion chip, and communicates with the MCU through serial ports TXD and RXD. J 10  is a USB interface which can be connected to an external USB cable to thereby communicate with the external equipments (for example, a computer, a tablet computer, etc.). DB 4  and DB 5  are protective diodes used to absorb the instantaneous large positive and negative voltages of PIN 2  and PIN 3  on J 10  to protect U 2 . 
     Compared with the conventional technology, the battery pack diagnostic method and the battery pack diagnostic device  100  of the present invention can quickly and comprehensively detect the battery pack, and accurately locate the fault location, thereby effectively improving the efficiency of maintenance personnel. 
     The above embodiment is only used to illustrate present invention and not to limits the technical solutions described in present invention. The understanding of this specification should be based on those skilled in the art, although present invention has been described in detail with reference to the above embodiment. However, those skilled in the art should understand that those skilled in the art can still modify or equivalently replace present invention, and all technical solutions and improvements that do not depart from the spirit and scope of present invention should be within the scope of the claims of the invention.