Sampling device of battery pack, battery pack and energy storage equipment

Abstract

The invention provides a sampling device of a battery pack, the battery pack and energy storage equipment, the battery pack comprises at least two battery cell modules, and the sampling device comprises a control circuit and a voltage sampling circuit; the adjacent battery cell modules are connected in series through conductive parts, and the voltage sampling circuit comprises a sampling unit and at least one switch unit; the switch unit comprises a first switch and a second switch; the control circuit is respectively connected with each switch unit, and controls one of the first switch and the second switch in each switch unit to be switched on and the other to be switched off, so that the sampling unit respectively collects voltage values at two ends of the conductive part. The voltage sampling result of the battery cell module can be confirmed according to the voltage values at the two ends of the conductive component, so that the voltage drop of the conductive component can be prevented from influencing the voltage sampling of the battery cell module, and the accuracy of the voltage sampling of the battery cell module is improved.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage power supply, and in particular to a sampling device for a battery pack, a battery pack and an energy storage device. Background Art

[0002] With the development of the new energy battery industry, the capacity requirements for battery packs (also known as battery modules, energy storage modules) are getting higher and higher. The battery pack usually includes multiple groups of battery cell modules, and multiple battery cell modules are generally connected in series using conductive parts such as jumper copper bars. Due to the internal resistance of the jumper copper bar, the voltage of the jumper copper bar is proportional to the current. When the battery pack is charged or discharged, the voltage drop on the jumper copper bar will cause the sampling chip to sample the battery cell voltage connected to the jumper copper bar. There is an error, which makes the voltage judgment of the battery pack incorrect. When the battery pack is charged and discharged, it is easy to trigger the battery cell voltage overvoltage protection or undervoltage protection in advance, resulting in the battery pack cannot be fully charged or discharged incompletely, and the actual storage capacity of the battery pack is reduced. Summary of the invention

[0003] In view of this, the present application provides a sampling device for a battery pack, a battery pack and an energy storage device, so as to improve the accuracy of voltage sampling of a battery cell module.

[0004] In a first aspect, the present application provides a sampling device for a battery pack, wherein the battery pack includes at least two battery cell modules, the sampling device includes a control circuit and a voltage sampling circuit, the battery cell module includes at least one battery cell; at least some adjacent battery cell modules are connected in series through a conductive member, and the voltage sampling circuit includes a sampling unit and at least one switch unit; the number of switch units is the same as the number of conductive members; the switch unit includes a first switch and a second switch, the first end of the first switch is used to connect to the first end of the conductive member, the first end of the second switch is used to connect to the second end of the conductive member, the second end of the first switch is connected to the second end of the second switch and connected to the sampling unit; the control circuit is connected to each switch unit respectively, and controls one of the first switch and the second switch in each switch unit to be turned on and the other to be turned off, so that the sampling unit collects the voltage values ​​at both ends of the conductive member respectively.

[0005] In the above embodiment, the sampling device includes a control circuit and a voltage sampling circuit. The voltage sampling circuit includes a sampling unit and a switch unit having the same number as the conductive member. The first switch and the second switch in the switch unit are respectively connected to the two ends of the conductive member, and the first switch and the second switch are both connected to the sampling unit. The control circuit is connected to each switch unit, and controls one of the first switch and the second switch in each switch unit to be turned on and the other to be turned off, so that the sampling unit can respectively collect the voltage values ​​at both ends of the conductive member, so that the voltage sampling result of the battery cell module can be confirmed according to the voltage values ​​at both ends of the conductive component, thereby preventing the voltage drop on the conductive member from affecting the voltage sampling of the battery cell module connected to the conductive member, thereby improving the accuracy of the voltage sampling of the battery cell module, and preventing the problem of a reduction in the actual storage capacity of the battery pack due to errors in the voltage sampling of the battery cell module.

[0006] In one of the embodiments, the sampling unit is also used to collect the module voltage of each battery cell module in a preset sampling period; the control circuit is also used to control the first switch and the second switch in the switch unit to be alternately turned on at least once in each sampling period, so as to collect the voltage value across the conductive member at least once; the control circuit is also used to correct the module voltage on the battery cell module adjacent to the conductive member in the corresponding sampling period according to the collected voltage value across the conductive member.

[0007] In one embodiment, the control circuit is also used to: obtain a first current flowing through the conductive member; determine a first voltage on the conductive member based on a voltage value at both ends of the conductive member collected by a sampling unit; determine an internal resistance of the conductive member based on the first current and the first voltage; and correct a module voltage of a battery cell module adjacent to the conductive member based on the internal resistance of the conductive member.

[0008] In one of the embodiments, the module voltage of the battery cell module adjacent to the conductive member is corrected according to the internal resistance of the conductive member, including: controlling one of the first switch and the second switch to maintain an on state and the other to maintain an off state; controlling the sampling unit to collect the module voltage on each battery cell module at a preset sampling period, and obtaining the real-time sampling current flowing through the conductive member during the corresponding sampling period; and correcting the module voltage of the battery cell module adjacent to the conductive member during the corresponding sampling period according to the internal resistance of the conductive member and the real-time sampling current.

[0009] In one embodiment, the control circuit corrects the module voltage of the battery cell module adjacent to the conductive component in the corresponding sampling period according to the internal resistance of the conductive component and the real-time sampling current, including: determining the real-time compensation voltage according to the internal resistance of the conductive component and the real-time sampling current; and correcting the module voltage of the battery cell module adjacent to the conductive component in the corresponding sampling period according to the real-time compensation voltage.

[0010] In one embodiment, the control circuit is further used to: control the sampling unit to collect the voltage value across the conductive member at a preset update period to re-determine the internal resistance of the conductive member; wherein the preset update period is greater than the preset sampling period.

[0011] In one embodiment, the control circuit is further used to: control the first switch and the second switch to switch the switch state in a preset switching cycle; wherein the preset switching cycle is greater than a preset sampling cycle.

[0012] In one embodiment, the control circuit is further configured to: after switching the switching states of the first switch and the second switch, control the sampling unit to collect the voltage value across the conductive member to re-determine the internal resistance of the conductive member.

[0013] A second aspect of the present application provides a battery pack, comprising at least two battery cell modules and a sampling device; the battery cell module comprises at least one battery cell; adjacent battery cell modules are connected in series via a conductive member, and the sampling device is the sampling device as described above.

[0014] A third aspect of the present application provides an energy storage device, including a battery pack as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic block diagram of the modules of the battery pack provided in an embodiment of the present application.

[0016] Figure 2 It is a schematic diagram of the circuit structure of the battery pack provided in an embodiment of the present application.

[0017] Figure 3 It is a schematic diagram of the circuit structure of the battery pack provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] It should be noted that the terms "first" and "second" in the specification, claims and drawings of the present application are used to distinguish similar objects rather than to describe a specific order or sequence.

[0019] It should also be noted that the method disclosed in the embodiments of the present application or the method shown in the flowchart includes one or more steps for implementing the method. Without departing from the scope of the claims, the execution order of multiple steps can be interchangeable with each other, and some of the steps can also be deleted.

[0020] Some embodiments will be described below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0021] A battery pack usually includes multiple groups of battery cell modules, and multiple battery cell modules are generally connected in series using conductive parts such as jumper copper bars. Due to the internal resistance of the jumper copper bar, the voltage of the jumper copper bar is proportional to the current. When the battery pack is charged or discharged, the voltage drop on the jumper copper bar will cause the sampling chip to have errors in sampling the voltage of the battery cell connected to the jumper copper bar, resulting in incorrect judgment of the battery pack voltage. When the battery pack is charged and discharged, it is easy to trigger the battery cell voltage overvoltage protection or undervoltage protection in advance, resulting in the battery pack cannot be fully charged or discharged incompletely, and the actual storage capacity of the battery pack is reduced.

[0022] Therefore, the embodiments of the present application provide a sampling device for a battery pack, a battery pack, and an energy storage device, so as to improve the accuracy of voltage sampling of a battery cell module and prevent the problem of a reduction in the actual storage capacity of the battery pack from occurring.

[0023] See also Figure 1 , Figure 1 The battery pack 10 provided in an embodiment of the present application is shown. The battery pack 10 includes at least two battery cell modules 100 and a sampling device 200 .

[0024] The battery cell module 100 includes at least one battery cell. When the battery cell module 100 includes one battery cell, the series connection between the battery cell modules 100 is also the series connection between the battery cells. When the battery cell module 100 includes multiple battery cells, the battery cells can be in series, in parallel, or in series-parallel. At least some of the adjacent battery cell modules 100 are connected in series through the conductive member 300. The conductive member 300 can be determined whether it needs to be set according to the arrangement between the battery cell modules 100. Usually, the battery cell modules 100 are arranged side by side when connected in series, but when limited by the spatial structure, they may also be arranged across rows. At this time, a conductive member is needed to realize the electrical connection between two adjacent battery cell modules in different rows. The conductive member 300 can be a copper bar structure, a copper bar structure, a copper sheet structure, etc. Of course, the conductive member 300 can also be composed of other conductive materials.

[0025] The battery pack 10 generally includes an output positive electrode P+ and an output negative electrode P−, so that the external load 20 can be connected through the output positive electrode P+ and the output negative electrode P− to supply power to the external load 20. The battery pack 10 can also be connected to an external power supply device 30 through the output positive electrode P+ and the output negative electrode P−, so that the battery pack 10 is charged by the external power supply device 30.

[0026] The sampling device 200 includes a control circuit 210 and a voltage sampling circuit 220. The voltage sampling circuit 220 includes a sampling unit 221 and at least one switch unit 222. The number of switch units 222 is the same as the number of conductive members 300 in the battery pack 10. The switch unit 222 includes a first switch S1 and a second switch S2. The first end of the first switch S1 is used to connect the first end of the conductive member 300. The second end of the second switch S2 is used to connect the second end of the conductive member 300. The second end of the first switch S1 is connected to the second end of the second switch S2 and connected to the sampling unit 221. The control circuit 210 is connected to each switch unit 222, and controls one of the first switch S1 and the second switch S2 in each switch unit 222 to be turned on and the other to be turned off, so that the sampling unit 221 collects the voltage values ​​at both ends of the conductive member 300, respectively. Specifically, when the first switch S1 is turned on and the second switch S2 is turned off, the first end of the conductive member 300 is connected to the sampling unit 221 through the turned-on first switch S1, and the sampling unit 221 collects the voltage value of the first end of the conductive member 300. When the first switch S1 is turned off and the second switch S2 is turned on, the sampling unit collects the voltage value of the second end of the conductive member 300. Based on this, the sampling unit 221 collects the voltage values ​​at both ends of the conductive member 300.

[0027] When the voltage of the cell module 100 is sampled, the module voltage of the cell module 100 connected to the conductive member 300 will include the voltage of the conductive member 300, so that the sampled module voltage has an error. The voltage value at both ends of the conductive member 300 is sampled by the sampling unit 221, and the voltage of the conductive member 300 can be confirmed according to the voltage value at both ends of the conductive member 300, and then the sampled module voltage can be corrected according to the voltage value of the conductive member 300.

[0028] In this way, the sampling unit 221 can respectively collect the voltage values ​​at both ends of each conductive member 300, and confirm the voltage sampling result of the battery cell module 100 according to the collected voltage values ​​at both ends of the conductive member 300, thereby preventing the voltage drop on the conductive member 300 from affecting the voltage sampling of the battery cell module 100 connected to the conductive member 300, improving the accuracy of the voltage sampling of the battery cell module 100, preventing the battery pack 10 from being unable to be fully charged or incompletely discharged during charging and discharging, and further preventing the problem of the actual storage capacity of the battery pack 10 being reduced due to errors in the voltage sampling of the battery cell module 100.

[0029] In the embodiment of the present application, the sampling unit 221 may include a sampling chip, which may be, for example, an analog front end chip (AFE) in the battery pack 10. The first switch S1 and the second switch S2 may be controllable switches such as relays, triodes, and transistors.

[0030] The control circuit 210 may include a battery management system (BMS), a microcontroller unit (MCU), a central processing unit (CPU), other general-purpose processors, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, etc.

[0031] In some embodiments, the sampling unit 221 may also be used to collect the module voltage of each battery cell module 100 at a preset sampling period.

[0032] The control circuit 210 can also be used to control the first switch S1 and the second switch S2 in the switch unit 222 to be alternately turned on at least once in each sampling period, so as to collect the voltage value across the conductive member 300 at least once, and correct the module voltage on the battery cell module 100 adjacent to the conductive member 300 in the corresponding sampling period according to the collected voltage value across the conductive member 300.

[0033] That is to say, the control circuit 210 controls the first switch S1 and the second switch S2 to be turned on alternately at least once in each sampling cycle of the sampling unit 221, so that in each sampling cycle, the module voltage of the battery cell module 100 adjacent to the conductive member 300 can be corrected according to the collected voltage value at both ends of the conductive member 300, and thus the module voltage collected in each sampling cycle is corrected according to the voltage value at both ends of the conductive member 300, so that the voltage sampling of the battery cell module 100 has better real-time performance and can improve the accuracy of the obtained module voltage.

[0034] In the embodiment of the present application, the control circuit 210 can be connected to the sampling unit 221 for communication, so as to obtain the module voltage of each battery cell module 100 and the voltage value at both ends of the conductive member 300 collected by the sampling unit 221. The control circuit 210 can control the charging and discharging of the battery pack 10, perform health management and safety protection on the battery pack 10, etc. according to the obtained module voltage. Among them, the control circuit 210 and the sampling unit 221 can be connected to each other for communication via an I2C bus, a CAN bus, etc.

[0035] See also Figure 2 and Figure 3 , shows a schematic structural diagram of a battery pack 10 including a plurality of battery cell modules 100 connected in series, wherein Figure 2 shows the current path when the battery pack 10 is discharged, Figure 3 The current path of the battery pack 10 when charging is shown. Correspondingly, the sampling unit 221 can be connected to both ends of each battery cell in the battery cell module 100 (the connection lines between some battery cell modules 100 and the sampling unit 221 are not drawn in the figure) and the second ends of the first switch S1 and the second switch S2 to collect the module voltage of each battery cell module 100 and the voltage across the conductive member 300, and correct the module voltage of the battery cell module 100 adjacent to the conductive member 300 according to the collected module voltage of each battery cell module 100 and the voltage across the conductive member 300.

[0036] Figure 2 and Figure 3 In the embodiment, each battery cell module 100 includes a single battery cell, and multiple battery cell modules 100 are connected in series, that is, multiple battery cells (B1 to Bn) are connected in series. The module voltage of the battery cell module 100 is also the battery cell voltage of the corresponding battery cell. It can be understood that in other embodiments, the battery cell module 100 can also include multiple battery cells connected in parallel.

[0037] Specifically, the voltages VC1 and VC2 collected by the sampling unit 221 are the voltages at both ends of the battery cell B2 (battery cell B2 is not adjacent to the conductive member 300), and the voltage of the battery cell B2 is VB2=VC2-VC1. The voltages VC4 and VC5 collected by the sampling unit 221 are the voltages at both ends of the battery cell B5 (battery cell B5 is not adjacent to the conductive member 300), and the voltage of the battery cell B5 is VB5=VC5-VC4. The sampling unit 221 collects the voltages of other battery cells that are not adjacent to the conductive member 300 in a similar manner, which will not be described in detail here.

[0038] When the control circuit 210 controls the first switch S1 to be turned on and the second switch S2 to be turned off, the voltage VC3 collected by the sampling unit 221 is the voltage V31 at the first end of the conductive member 300. When the control circuit 210 controls the first switch S1 to be turned off and the second switch S2 to be turned on, the voltage VC3 collected by the sampling unit 221 is the voltage V32 at the second end of the conductive member 300.

[0039] It can be understood that when the sampling unit 221 collects the voltage of the battery cell B4 connected to the first end of the conductive member 300, if the control circuit 210 controls the first switch S1 to be turned on and the second switch S2 to be turned off, the voltages at both ends of the battery cell B4 collected by the sampling unit 221 will be VC4 and V31 respectively, and correspondingly, the voltage VB4 of the battery cell B4 = VC4-V31.

[0040] When the sampling unit 221 collects the voltage of the battery cell B3 connected to the second end of the conductive member 300, the control circuit 210 controls the first switch S1 to be turned off and the second switch S2 to be turned on, so that the voltages at both ends of the battery cell B3 collected by the sampling unit 221 are VC2 and V32 respectively, and correspondingly, the voltage VB3 of the battery cell B3 = V32-VC2.

[0041] Based on this, the sampling unit 221 collects the voltage of the battery cell connected to the conductive member 300 without being affected by the voltage drop of the conductive member 300 , and can more accurately obtain the voltage of the battery cell connected to the conductive member 300 , thereby more accurately obtaining the module voltage of the battery cell module 100 .

[0042] In this embodiment, the first switch S1 and the second switch S2 are controlled to be turned on alternately in each sampling period to obtain the voltage at the position corresponding to the cell module 100 adjacent to the conductive member 300, and then determine the actual voltage on the adjacent cell module 100. In the above embodiment, the module voltage can be obtained in real time and accurately.

[0043] In some other embodiments, the control circuit 210 may also be used to obtain a first current flowing through the conductive member 300. The control circuit 210 determines a first voltage on the conductive member 300 according to the voltage value at both ends of the conductive member 300 collected by the sampling unit 221. The control circuit 210 determines the internal resistance of the conductive member 300 according to the first current and the first voltage, and corrects the module voltage of the battery cell module 100 adjacent to the conductive member 300 according to the internal resistance of the conductive member 300.

[0044] Among them, Figures 2 to 3 As shown, the first voltage V on the conductive member 300 R0 =V31-V32. The internal resistance R0 of the conductive member 300 = V R0 / I, where I is the first current. It can be understood that in order to improve the accuracy of the internal resistance of the conductive member 300 obtained, the control circuit 210 can control the first switch S1 and the second switch S2 to be turned on alternately for multiple times, and each time the internal resistance of the conductive member 300 is determined according to the collected first current and the collected first voltage, and the average value of the internal resistances obtained for multiple times is used as the internal resistance of the conductive member 300. By using the internal resistance of the conductive member 300 obtained, the voltage of the adjacent battery module 100 sampled subsequently can be corrected without collecting the voltage at both ends of the conductive member 300 in each sampling cycle, thereby improving the sampling efficiency while ensuring the sampling accuracy.

[0045] Further, after the internal resistance of the conductive member 300 is determined, the control circuit 210 can control one of the first switch S1 and the second switch S2 to remain in the on state and the other to remain in the off state. The control circuit 210 controls the sampling unit 221 to collect the module voltage on each battery module 100 at a preset sampling period, and obtain the real-time sampling current flowing through the conductive member 300 in the corresponding sampling period. The control circuit 210 corrects the module voltage of the battery module 100 adjacent to the conductive member 300 in the corresponding sampling period according to the internal resistance of the conductive member 300 and the real-time sampling current.

[0046] That is, after determining the internal resistance of the conductive member 300 , the control circuit 210 controls one of the first switch S1 and the second switch S2 to remain in an on state and the other to remain in an off state instead of alternating conduction, thereby reducing the loss of the battery pack 10 .

[0047] It can be understood that a current detection circuit is provided in the battery pack 10 to detect the real-time sampling current in real time during each sampling cycle.

[0048] Furthermore, the control circuit 210 determines a real-time compensation voltage according to the internal resistance of the conductive member 300 and the real-time sampling current, and then corrects the module voltage of the battery cell module 100 adjacent to the conductive member 300 in the corresponding sampling period according to the real-time compensation voltage.

[0049] When the sampling unit 221 collects the module voltage of each battery module 100, if the first switch S1 remains in the off state and the second switch S2 remains in the on state, the sampling unit 221 samples the battery module 100 (such as Figure 2 The voltage collected by B3 in FIG. 1 is the actual module voltage, and the cell module 100 (eg, Figure 2 B4) in the example needs to correct the collected module voltage according to the real-time compensation voltage.

[0050] Specifically, when the battery pack 10 is in the state of supplying power to the load 20, the sampling unit 221 collects the voltage V4=VC4-V32 across the battery cell B4. At this time, the potential of the conductive member 300 is negative at the top and positive at the bottom. According to Kirchhoff's law, it can be obtained that the collected voltage V4 satisfies the following relationship:

[0051] V4=VB4+(-V R0 )

[0052] The voltage V4 of the cell B4 collected by the sampling unit 221 is corrected according to the real-time compensation voltage to obtain the corrected voltage VB4 of the cell B4 = V4 - (-V R0 )=V4+V R0=V4+Io*R0, to achieve the correction of the module voltage, where Io is the discharge current of the battery pack 10. It can be understood that since each battery cell is in a discharge state, the voltage direction of the conductive member 300 will be opposite to the voltage direction of each battery cell, so the corrected voltage VB4 of the battery cell B4 will be greater than the voltage V4 collected by the sampling unit 221.

[0053] When the battery pack 10 is being charged by the external power supply device 30, the sampling unit 221 collects the voltage V4=VC4-V32 across the battery cell B4. At this time, the potential of the conductive member 300 is positive at the top and negative at the bottom. According to Kirchhoff's law, the collected voltage V4 satisfies the following relationship:

[0054] V4=VB4+V R0

[0055] The voltage V4 collected by the battery cell B4 is corrected according to the real-time compensation voltage, and the corrected voltage VB4 of the battery cell B4 is obtained as VB4 = V4 - V R0 =V4-Ii*R0, to achieve the correction of the module voltage, where Ii is the charging current of the battery pack 10. It can be understood that since each battery cell is in a charging state, the voltage direction of the conductive member 300 will be the same as the voltage direction of each battery cell, so the corrected voltage VB4 of the battery cell B4 will be smaller than the voltage V4 collected by the sampling unit 221.

[0056] It can be understood that if the control circuit 210 controls the first switch S1 to remain in the on state and the second switch S2 to remain in the off state, the voltage collected by the sampling unit 221 at both ends of the battery cell B4 is its actual module voltage, and the voltage collected by the sampling unit 221 at both ends of the battery cell B3 is actually the voltage of the battery cell B3 and the conductive member 300. Therefore, the control circuit 210 can directly determine the module voltage of the battery cell B4 according to the voltage of the battery cell B4 collected by the sampling unit 221, and correct the module voltage of the battery cell B3 collected by the collection unit 221 according to the real-time compensation voltage. Among them, the control circuit 210 corrects the voltage of the battery cell B3 according to the real-time compensation voltage, which is the same as the aforementioned correction of the voltage of the battery cell B4, and will not be repeated here.

[0057] In some embodiments, the control circuit 210 may also be used to control the sampling unit 221 to collect the voltage value across the conductive member 300 at a preset update period to re-determine the internal resistance of the conductive member 300. The preset update period is greater than the preset sampling period.

[0058] The control circuit 210 controls the sampling unit 221 to collect the voltage value across the conductive member 300 at a preset update cycle, that is, the control circuit 210 controls the first switch S1 and the second switch S2 to be turned on alternately at least once in each update cycle, so that the sampling unit 221 can collect the voltage value across the conductive member 300, and then re-determine the internal resistance of the conductive member 300. In this way, it is possible to avoid deviations in the real-time compensation voltage caused by changes in the internal resistance of the conductive member 300 as it ages with use, and the voltage sampling accuracy of the battery module can be further improved.

[0059] In some embodiments, the control circuit 210 may also be used to control the first switch S1 and the second switch S2 to switch states at a preset switching period, wherein the preset switching period is greater than a preset sampling period.

[0060] For example, in the previous switching cycle, the control circuit 210 controls the first switch S1 to remain in the on state and the second switch S2 to remain in the off state. In the next switching cycle, the control circuit 210 controls the first switch S1 to remain in the off state and the second switch S2 to remain in the on state, so that the first switch S1 and the second switch S2 switch the switch state. In this way, it is possible to prevent one of the first switch S1 and the second switch S2 from working for a long time and being easily damaged by aging, thereby preventing the stability of the battery pack 10 from being affected by the aging and damage of the first switch S1 and the second switch S2.

[0061] Further, after switching the switch states of the first switch S1 and the second switch S2 , the control circuit 210 may also be used to control the sampling unit 221 to collect the voltage value across the conductive member 300 to re-determine the internal resistance of the conductive member 300 .

[0062] In this example, after the control circuit 210 controls the first switch S1 and the second switch S2 to switch the switch state in each switching cycle, it can control the sampling unit 221 to re-collect the voltage value across the conductive member 300 to re-determine the internal resistance of the conductive member 300 and timely update the internal resistance of the conductive member 300.

[0063] In some embodiments, the end of each battery cell and the sampling end of the sampling unit 221 may be connected via a current limiting resistor to limit the current of the connection path between the battery cell and the sampling unit 221, thereby preventing the connection path between the battery cell and the sampling unit 221 from being too large and damaging the sampling unit 221. The resistance value of the current limiting resistor may be set to 100Ω, 120Ω, etc., and may be set according to actual application requirements.

[0064] The embodiment of the present application further provides an energy storage device (not shown), comprising the battery pack 10 as described above.

[0065] In some embodiments, the energy storage device may further include a power conversion device (not shown). The battery pack 10 and the power conversion device may be separate structures or may be an integrated structure.

[0066] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present application.

Claims

1. A sampling device for a battery pack, the battery pack comprising at least two battery modules, the sampling device comprising a control circuit and a voltage sampling circuit, the battery module comprising at least one battery cell; at least some of the adjacent battery modules are connected in series through a conductive member, characterized in that: The voltage sampling circuit includes a sampling unit and at least one switch unit; the number of the switch units is the same as the number of the conductive members; the switch unit includes a first switch and a second switch, the first end of the first switch is used to connect the first end of the conductive member, the first end of the second switch is used to connect to the second end of the conductive member, the second end of the first switch is connected to the second end of the second switch and connected to the sampling unit; the control circuit is respectively connected to each of the switch units, and controls one of the first switch and the second switch in each of the switch units to be turned on and the other to be turned off, so that the sampling unit respectively collects the voltage values ​​at both ends of the conductive member.

2. The sampling device according to claim 1, characterized in that: The sampling unit is also used to collect the module voltage of each of the battery cell modules in a preset sampling period; the control circuit is also used to control the first switch and the second switch in the switch unit to be alternately turned on at least once in each sampling period, so as to collect the voltage value across the conductive member at least once; the control circuit is also used to correct the module voltage on the battery cell module adjacent to the conductive member in the corresponding sampling period according to the collected voltage value across the conductive member.

3. The sampling device according to claim 1, characterized in that: The control circuit is also used for: obtaining a first current flowing through the conductive member; Determine a first voltage on the conductive member according to the voltage value at both ends of the conductive member collected by the sampling unit; determining an internal resistance of the conductive member according to the first current and the first voltage; The module voltage of the battery cell module adjacent to the conductive member is corrected according to the internal resistance of the conductive member.

4. The sampling device according to claim 3, characterized in that: The method of correcting the module voltage of the battery module adjacent to the conductive member according to the internal resistance of the conductive member comprises: Controlling one of the first switch and the second switch to remain in an on state and the other to remain in an off state; Controlling the sampling unit to collect the module voltage on each of the battery cell modules at a preset sampling period, and obtaining a real-time sampling current flowing through the conductive member during the corresponding sampling period; The module voltage of the battery cell module adjacent to the conductive member in the corresponding sampling period is corrected according to the internal resistance of the conductive member and the real-time sampled current.

5. The sampling device according to claim 4, characterized in that: The control circuit corrects the module voltage of the battery module adjacent to the conductive member in the corresponding sampling period according to the internal resistance of the conductive member and the real-time sampling current, including: Determining a real-time compensation voltage according to the internal resistance of the conductive member and the real-time sampled current; The module voltage of the battery cell module adjacent to the conductive member in the corresponding sampling period is corrected according to the real-time compensation voltage.

6. The sampling device according to claim 4 or 5, characterized in that: The control circuit is also used to: control the sampling unit to collect the voltage value across the conductive member at a preset update period to re-determine the internal resistance of the conductive member; wherein the preset update period is greater than the preset sampling period.

7. The sampling device according to claim 4 or 5, characterized in that: The control circuit is also used for: The first switch and the second switch are controlled to switch switch states in a preset switching cycle; wherein the preset switching cycle is greater than the preset sampling cycle.

8. The sampling device according to claim 7, characterized in that: The control circuit is also used for: After the switch states of the first switch and the second switch are switched, the sampling unit is controlled to collect the voltage value across the conductive member to re-determine the internal resistance of the conductive member.

9. A battery pack, comprising at least two battery modules and a sampling device; the battery module comprises at least one battery cell; adjacent battery modules are connected in series via a conductive member, characterized in that: The sampling device is the sampling device according to any one of claims 1 to 8.

10. An energy storage device, characterized in that: Comprising the battery pack as claimed in claim 9.

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