A battery management system and voltage acquisition device thereof

Abstract

The present invention belongs to the field of power management technology, and provides a battery management system and a voltage acquisition device thereof. The voltage acquisition device provided by the present invention includes a first acquisition channel, a second acquisition channel, an acquisition channel control module, a microprocessor and an analog-to-digital conversion module. During the charging and discharging process of the power battery pack, the microprocessor outputs a plurality of control signals in a preset order; the acquisition channel control module controls the first acquisition channel and the second acquisition channel to sequentially connect the positive and negative poles of each battery to the analog-to-digital conversion module according to the plurality of control signals; the analog-to-digital conversion module acquires the voltage of each battery, and outputs the acquisition result to the microprocessor, so that the microprocessor monitors the voltage of each battery. Since the voltage acquisition device acquires the voltage at both ends of each battery in a scanning manner one by one, the acquired voltage is within the standard voltage range, thereby improving the voltage acquisition accuracy of the voltage acquisition device.

Description

Technical Field

[0001] The present invention belongs to the technical field of power management, and in particular relates to a battery management system and a voltage acquisition device thereof. Background Art

[0002] With the vigorous development of new energy, power batteries have been widely used. Power batteries can provide power sources for electric vehicles, electric trains, electric bicycles, etc. In order to achieve high voltage and high capacity, power batteries are generally composed of multiple batteries connected in series or in parallel. In order to improve the utilization rate of power batteries, prevent overcharging and over-discharging of power batteries, and increase the life of power batteries, it is necessary to equip the power battery pack with a battery management system (Battery Management System, BMS). BMS can collect the voltage, temperature, current, etc. of each battery in the power battery pack to monitor the working status of each battery in the power battery.

[0003] However, when the voltage acquisition module of the existing BMS acquires the voltage of each battery, it uses the total negative (the negative pole of the last battery) or the total positive (the positive pole of the first battery) as a common reference acquisition point, and accumulates or subtracts the voltage of each battery one by one. This voltage acquisition method will increase the voltage represented by each acquisition data unit, resulting in a decrease in the voltage acquisition accuracy of the acquisition module.

[0004] In summary, the voltage acquisition module of the existing BMS has the problem of low voltage acquisition accuracy. Summary of the invention

[0005] The object of the present invention is to provide a battery management system and a voltage acquisition device thereof, aiming to solve the problem of low voltage acquisition accuracy existing in the voltage acquisition device of the existing battery management system.

[0006] The present invention is implemented as follows: a voltage acquisition device of a battery management system is connected to a power battery pack composed of n batteries connected in series, where n is an integer greater than or equal to 2; the n batteries are connected in series to the nth battery in sequence starting from the first battery in a manner that the negative electrode of the previous battery is connected to the positive electrode of the next battery; the voltage acquisition device is used to acquire the voltage of each of the batteries; the voltage acquisition device includes: a first acquisition channel, a second acquisition channel, an acquisition channel control module, a microprocessor and an analog-to-digital conversion module;

[0007] The first acquisition channel and the second acquisition channel are both connected to the acquisition channel control module and the analog-to-digital conversion module, and the microprocessor is connected to the acquisition channel control module and the analog-to-digital conversion module;

[0008] During the charging and discharging process of the power battery pack, the microprocessor outputs a plurality of control signals to the acquisition channel control module in a preset order; the acquisition channel control module controls the first acquisition channel and the second acquisition channel to connect the positive and negative electrodes of each battery to the analog-to-digital conversion module in sequence in a preset order according to the plurality of control signals; the analog-to-digital conversion module acquires the voltage of each battery and outputs the acquisition result to the microprocessor, so that the microprocessor monitors the voltage of each battery.

[0009] The present invention also provides a battery management system, which includes the voltage acquisition device mentioned above.

[0010] The voltage acquisition device provided by the present invention includes a first acquisition channel, a second acquisition channel, an acquisition channel control module, a microprocessor and an analog-to-digital conversion module. During the charging and discharging process of the power battery pack, the microprocessor outputs multiple control signals to the acquisition channel control module in a preset order; the acquisition channel control module controls the first acquisition channel and the second acquisition channel to connect the positive and negative electrodes of each battery to the analog-to-digital conversion module in a preset order according to the multiple control signals; the analog-to-digital conversion module acquires the voltage of each battery and outputs the acquisition result to the microprocessor, so that the microprocessor monitors the voltage of each battery. Since the voltage acquisition device acquires the voltage at both ends of each battery in a scanning manner one by one, the acquired voltage is within the standard voltage range, thereby improving the voltage acquisition accuracy of the voltage acquisition device. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a module structure diagram of a voltage acquisition device provided by an embodiment of the present invention;

[0012] Figure 2 is a module structure diagram of a voltage acquisition device provided by another embodiment of the present invention;

[0013] Figure 3 is a module structure diagram of a voltage acquisition device provided by another embodiment of the present invention;

[0014] Figure 4 is a circuit structure diagram of a voltage acquisition device provided by an embodiment of the present invention;

[0015] Figure 5 It is a circuit structure diagram of a bipolar conversion unit in a voltage acquisition device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0017] It should be noted that the term "comprising" and any variations thereof in the specification and claims of the present invention are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices. In addition, the terms "first", "second" and "third" etc. are used to distinguish different objects, rather than to describe a specific order.

[0018] Figure 1 The module structure of a voltage acquisition device of a battery management system provided by an embodiment of the present invention is shown. For the convenience of description, only the part related to the embodiment of the present invention is shown, which is described in detail as follows:

[0019] like Figure 1 As shown, a voltage acquisition device 1 of a battery management system is connected to a power battery pack 2 composed of n batteries connected in series, where n is an integer greater than or equal to 2. The n batteries are connected in series from the first battery to the nth battery in the manner of connecting the negative electrode of the previous battery to the positive electrode of the next battery. In practical applications, the n batteries can be lithium batteries or other types of storage batteries, which are set according to actual conditions and are not limited here.

[0020] The voltage acquisition device 1 is used to acquire the voltage of each battery. Specifically, the voltage acquisition device 1 includes: a first acquisition channel 10 , a second acquisition channel 20 , an acquisition channel control module 30 , a microprocessor 40 and an analog-to-digital conversion module 50 .

[0021] The first acquisition channel 10 and the second acquisition channel 20 are both connected to the acquisition channel control module 30 and the analog-to-digital conversion module 50 , and the microprocessor 40 is connected to the acquisition channel control module 30 and the analog-to-digital conversion module 50 .

[0022] During the charging and discharging process of the power battery pack 2, the microprocessor 40 outputs multiple control signals to the acquisition channel control module 30 in a preset order; the acquisition channel control module 30 controls the first acquisition channel 10 and the second acquisition channel 20 to connect the positive and negative electrodes of each battery to the analog-to-digital conversion module 50 in sequence in a preset order according to the multiple control signals; the analog-to-digital conversion module 50 acquires the voltage of each battery and outputs the acquisition result to the microprocessor 40, so that the microprocessor 40 monitors the voltage of each battery.

[0023] It should be noted that in the embodiment of the present invention, the microprocessor 40 is also connected to other modules such as the charging module and the discharging module in the battery management system (not shown in the figure), that is, the microprocessor 40 can detect the charging process or the discharging process of the power battery pack 2 .

[0024] During the charging or discharging process of the power battery pack 2, the microprocessor 40 outputs multiple control signals to the acquisition channel control module 30 in a preset order. The multiple control signals are specifically used to control the first acquisition channel 10 and the second acquisition channel 20 to connect the positive and negative electrodes of each battery to the analog-to-digital conversion module 50 in sequence in a preset order, so that the analog-to-digital conversion module 50 collects the voltage of each battery respectively. For example, if the control signal output by the microprocessor 40 is a control signal for connecting the first battery to the analog-to-digital conversion module 50, the acquisition channel control module 30 controls the first acquisition channel 10 and the second acquisition channel 20 to connect the positive and negative electrodes of the first battery to the analog-to-digital conversion module 50; if the control signal output by the microprocessor 40 is a control signal for connecting the third battery to the analog-to-digital conversion module, the acquisition channel control module 30 controls the first acquisition channel 10 and the second acquisition channel 20 to connect the positive and negative electrodes of the third battery to the analog-to-digital conversion module 50, and so on. Each control signal only controls the connection of the positive and negative electrodes of one battery to the analog-to-digital conversion module 50, so that the analog-to-digital conversion module 50 collects the voltage of each battery in turn.

[0025] In the embodiment of the present invention, the preset order can be set according to actual needs and is not limited here.

[0026] For example, the preset order may be from the 1st battery to the nth battery. That is, the multiple control signals successively output by the microprocessor 40 correspond to the 1st battery to the nth battery respectively; the acquisition channel control module 30 controls the first acquisition channel 10 and the second acquisition channel 2 to sequentially connect the positive and negative electrodes of the 1st battery to the positive and negative electrodes of the nth battery to the analog-to-digital conversion module 50 according to the multiple control signals.

[0027] Of course, the preset order can also be from the nth battery to the first battery. That is, the multiple control signals successively output by the microprocessor 40 correspond to the nth battery to the first battery respectively; the acquisition channel control module 30 controls the first acquisition channel 10 and the second acquisition channel 2 to sequentially connect the positive and negative electrodes of the nth battery to the positive and negative electrodes of the first battery to the analog-to-digital conversion module 50 according to the multiple control signals.

[0028] Since the voltage collected by the analog-to-digital conversion module 50 each time is only the voltage of one battery, compared with the existing collection method of using the total negative or total positive as a common reference collection point and accumulating or subtracting one by one to obtain the voltage of each battery, the voltage collection device in the embodiment of the present invention has higher voltage collection accuracy and can avoid high voltage breakdown of the power circuit, thereby improving the reliability of the system.

[0029] In the embodiment of the present invention, when the positive electrode and the negative electrode of each battery are connected to the analog-to-digital conversion module 50, the first acquisition channel 10 and the second acquisition channel 20 are connected to the positive electrode and the negative electrode of the battery respectively.

[0030] In the embodiment of the present invention, the microprocessor 40 can be implemented by a CPU (Central Processing Unit), a single-chip microcomputer, etc., and is specifically configured according to actual conditions and is not limited here.

[0031] In the embodiment of the present invention, both the first collection channel 10 and the second collection channel 20 may be transmission lines.

[0032] Figure 2 The module structure of a voltage acquisition device provided by another embodiment of the present invention is shown. For the convenience of description, only the part related to the embodiment of the present invention is shown, which is described in detail as follows:

[0033] like Figure 2 As shown, the voltage acquisition device 1 further includes a voltage equalization module 60 .

[0034] The voltage equalization module 60 is connected to the first acquisition channel 10 , the second acquisition channel 20 and the microprocessor 40 .

[0035] After the power battery pack 2 is charged and discharged, the microprocessor 40 determines the voltage of each battery. If the voltage of at least one battery among the n batteries is lower than the preset voltage threshold, the microprocessor 40 outputs a corresponding balancing signal to the acquisition channel control module 30; the acquisition channel control module 30 controls the first acquisition channel 10 and the second acquisition channel 20 to connect the positive and negative electrodes of the corresponding batteries whose voltages are lower than the preset voltage threshold to the voltage balancing module 60 according to the balancing signal; the voltage balancing module 60 charges the corresponding batteries whose voltages are lower than the preset voltage threshold under the control of the microprocessor 40, so that the voltages of the corresponding batteries whose voltages are lower than the preset voltage threshold are maintained within the preset voltage range, thereby making the voltage of each battery reach a balanced state.

[0036] In the embodiment of the present invention, when it is detected that the charging or discharging process of the power battery pack 2 is completed, the microprocessor 40 determines the voltage of each battery respectively. If the voltage of at least one battery among the n batteries is lower than the preset voltage threshold, the microprocessor 40 outputs a corresponding equalization signal to the acquisition channel control module 30. For example, if the microprocessor 40 detects that the voltage of the first battery is lower than the preset threshold after the charging or discharging of the power battery pack 2 is completed, the microprocessor 40 outputs a control signal to connect the first battery to the voltage equalization module 60 to the acquisition channel control module 30, and the acquisition channel control module 30 controls the first acquisition channel 10 and the second acquisition channel 20 to connect the positive and negative electrodes of the first battery to the voltage equalization module 60, so that the voltage equalization module 60 charges the first battery, thereby maintaining the voltage of the first battery within the preset voltage range.

[0037] In the embodiment of the present invention, both the preset voltage threshold and the preset voltage range can be set according to actual conditions and are not limited here.

[0038] Figure 3 The module structure of a voltage acquisition device provided by another embodiment of the present invention is shown. For the convenience of description, only the part related to the embodiment of the present invention is shown, which is described in detail as follows:

[0039] like Figure 3 As shown, as an embodiment of the present invention, the acquisition channel control module 30 includes a decoding unit 301 and (n+1) switch units U1-U(n+1); the decoding unit 301 includes (n+1) output terminals.

[0040] Assume that there are n batteries BT1 to BTn.

[0041] The input end of the decoding unit 301 is connected to the microprocessor 40, and the first output end to the (n+1)th output end of the decoding unit 301 are respectively connected to the first input end of the first switch unit U1 to the first input end of the (n+1)th switch unit U(n+1); the first output end of the first switch unit U1 to the first output end of the nth switch unit Un are respectively connected to the positive electrode of the first battery BT1 to the positive electrode of the nth battery BTn, and the first output end of the (n+1)th switch unit U(n+1) is respectively connected to the positive electrode of the nth battery BTn. The negative electrode of each battery BTn is connected; the second output end of one switch unit (for example, the second switch unit U2) of two adjacent switch units (for example, the first switch unit U1 and the second switch unit U2) is connected to the first collection channel 10, and the second output end of the other switch unit (for example, the first switch unit U1) is connected to the second collection channel 20, that is, the second output ends of the first switch unit U1 to the (n+1)th switch unit U(n+1) are alternately connected to the first collection channel 10 and the second collection channel 20.

[0042] During the charging and discharging process of the power battery pack 2, the decoding unit 301 decodes the multiple control signals output by the microprocessor 40, and outputs multiple groups of acquisition level information corresponding to the multiple control signals; the (n+1) switch units U1~U(n+1) control the first acquisition channel 10 and the second acquisition channel 20 to connect the positive and negative electrodes of the n batteries BT1~BTn to the analog-to-digital conversion module 50 in a preset order according to the multiple groups of acquisition level information, so that the analog-to-digital conversion module 50 collects the voltages of the n batteries BT1~BTn respectively.

[0043] After the power battery pack 2 is charged and discharged, the decoding unit 301 decodes the equalization signal output by the microprocessor 40, and outputs the equalization level information corresponding to the equalization signal; the (n+1) switch units U1~U(n+1) control the first acquisition channel 10 and the second acquisition channel 20 to connect the positive and negative electrodes of the corresponding batteries whose voltages are lower than the preset voltage threshold to the voltage equalization module 60 according to the equalization level information, so that the voltage equalization module 60 charges the corresponding batteries.

[0044] In the embodiment of the present invention, the second output ends of the first switch unit U1 to the (n+1)th switch unit U(n+1) are respectively alternately connected to the first acquisition channel 10 and the second acquisition channel 20. Specifically, the second output ends of the odd-numbered switch units (U1, U3, U5, etc.) are connected to the second acquisition channel 20, and the second output ends of the even-numbered switch units (U2, U4, U6, etc.) are connected to the first acquisition channel 10 (e.g. Figure 3 As shown); or the second output end of the odd-numbered switch units (U1, U3, U5, etc.) is connected to the first acquisition channel 10, and the second output end of the even-numbered switch units (U2, U4, U6, etc.) is connected to the second acquisition channel 20 (not shown in the figure), which is set according to actual conditions and is not limited here.

[0045] In the embodiment of the present invention, the decoding unit 301 decodes each control signal or each equalization signal output by the microprocessor 40 into two sets of level information.

[0046] Specifically, during the charging or discharging process of the power battery pack 2, if the control signal output by the microprocessor 40 is a control signal for connecting the first battery BT1 to the analog-to-digital conversion module 50, the decoding unit 301 decodes the control signal and outputs two sets of sampling level information corresponding to the control signal through its multiple output terminals. One set of sampling level information is used to control the first switch unit U1 to open, so that the first switch unit U1 controls the second acquisition channel 20 to connect the positive electrode of the first battery BT1 to the analog-to-digital conversion module 50; the other set of sampling level information is used to control the second switch unit U2 to open, so that the second switch unit U2 controls the first acquisition channel 10 to connect the negative electrode of the first battery BT1 to the analog-to-digital conversion module 50, thereby enabling the analog-to-digital conversion module 50 to collect the voltage of the first battery BT1. If the control signal output by the microprocessor 40 is a control signal for connecting the third battery BT3 to the analog-to-digital conversion module 50, the decoding unit 301 decodes the control signal and outputs two sets of sampling level information corresponding to the control signal through its multiple output terminals. One set of sampling level information is used to control the third switch unit U3 to open, so that the third switch unit U3 controls the second acquisition channel 20 to connect the positive electrode of the third battery BT3 to the analog-to-digital conversion module 50; the other set of sampling level information is used to control the fourth switch unit U4 to open, so that the fourth switch unit U4 controls the first acquisition channel 10 to connect the negative electrode of the third battery BT3 to the analog-to-digital conversion module 50, and then the analog-to-digital conversion module 50 collects the voltage of the third battery BT3. The collection of the voltages of other batteries is the same as the above method, which will not be repeated here.

[0047] After the power battery pack 2 is charged and discharged, if the microprocessor 40 determines that the voltage of the first battery BT1 is lower than the preset threshold, the microprocessor 40 outputs an equalization signal to connect the first battery BT1 to the voltage equalization module 60, and the decoding unit 301 decodes the equalization signal and outputs two sets of equalization level information corresponding to the equalization signal; one set of equalization level information is used to control the first switch unit to open, so that the first switch unit controls the second acquisition channel 20 to connect the positive electrode of the first battery BT1 to the voltage equalization module 60; the other set of equalization level information is used to control the second switch unit U2 to open, so that the second switch unit U2 controls the first acquisition channel 10 to connect the negative electrode of the first battery BT1 to the voltage equalization module 60, thereby enabling the voltage equalization module 60 to charge the first battery BT1.

[0048] As an embodiment of the present invention, the voltage equalization module 60 includes a power supply 602 and a polarity conversion unit 601 .

[0049] The positive and negative electrodes of the power supply 601 are respectively connected to the positive input terminal and the negative input terminal of the polarity conversion unit 601, the first output terminal and the second output terminal of the polarity conversion unit 601 are respectively connected to the first acquisition channel 10 and the second acquisition channel 20, and the controlled end of the polarity conversion unit 60 is connected to the microprocessor 40.

[0050] When charging the corresponding battery, the polarity conversion unit 601 connects the positive electrode and the negative electrode of the power source 602 to the positive electrode and the negative electrode of the corresponding battery whose voltage is lower than the preset voltage threshold, respectively.

[0051] In the embodiment of the present invention, when the voltage of each battery is collected or the battery whose voltage is less than the preset voltage threshold is charged, a collection channel is shared, thereby saving circuit board space and cost, and a larger balancing current can be designed on the circuit board without being limited by space or heat generation. In addition, the same power supply is used to charge the battery whose voltage is less than the preset voltage threshold, so that the power of the power supply can be relatively large.

[0052] Figure 4 The circuit structure of a voltage acquisition device provided by an embodiment of the present invention is shown. For the convenience of description, only the part related to the embodiment of the present invention is shown, which is described in detail as follows:

[0053] like Figure 4 As shown in FIG. 1 , as an embodiment of the present invention, the switch units U1 ˜U(n+1) are all photoelectric couplers.

[0054] The first input terminal, the second input terminal, the first output terminal and the second output terminal of the photoelectric coupler are respectively the first input terminal, the second input terminal, the first output terminal and the second output terminal of the switch units U1 to U(n+1).

[0055] In an embodiment of the present invention, the photoelectric coupler is a resistive photoelectric coupler.

[0056] As an embodiment of the present invention, the decoding unit 301 includes a first decoder 310 and a second decoder 320. The first decoder 310 and the second decoder 320 each include an input terminal and (n+1) output terminals.

[0057] The input end of the first decoder 310 and the input end of the second decoder 320 constitute the input end of the decoding unit 301, the 1st output end to the (n+1)th output end of the first decoder 310 are respectively connected to the 1st output end to the (n+1)th output end of the second decoder 320, and the 1st output end to the (n+1)th output end of the first decoder 310 are respectively the 1st output end to the (n+1)th output end of the decoding unit 301.

[0058] In the embodiment of the present invention, the first decoder 310 and the second decoder 320 can both use existing decoders, which are specifically configured according to actual conditions and are not limited here. For example, when the acquisition channel control module 30 includes 8 switch units, the first decoder 310 and the second decoder 320 can use 3-line to 8-line decoders.

[0059] Assume that the power battery pack 2 includes 7 batteries BT1 to BT7, the acquisition channel control module 30 includes 8 switch units U1 to U8, and the first decoder 310 and the second decoder 320 are both 3-wire to 8-wire decoders. If the microprocessor 40 is to control the positive and negative electrodes of the first battery BT1 to be connected to the analog-to-digital conversion module 50 or the voltage equalization module 60, the microprocessor 40 outputs a control signal or an equalization signal for connecting the positive and negative electrodes of the first battery BT1 to the analog-to-digital conversion module 50 or the voltage equalization module 60. The control signal or the equalization signal corresponds to two sets of digital signals, that is, the microprocessor 40 outputs 000 and 001 to the first decoder 310 and the second decoder 320 respectively; the first decoder 310 outputs 10000000 (corresponding to the first output terminal 10000000, respectively). The first photocoupler U1 is turned on, and the first photocoupler U1 connects the positive electrode of the first battery BT1 to the analog-to-digital conversion module 50 or the voltage equalization module 60; the second decoder 320 outputs 01000000 (corresponding to the level signals output from the first output terminal to the (n+1)th output terminal, respectively). At this time, the second photocoupler U2 is turned on, and the second photocoupler U2 connects the negative electrode of the first battery BT1 to the analog-to-digital conversion module 50 or the voltage equalization module 60. The method by which the microprocessor 40 controls the first decoder 310 and the second decoder 320 to connect other batteries to the analog-to-digital conversion module 50 or the voltage equalization module 60 is the same as described above and will not be repeated here.

[0060] As an embodiment of the present invention, the analog-to-digital conversion module 50 includes a first analog-to-digital converter 501 and a second analog-to-digital converter 502 .

[0061] The first input terminal and the second input terminal of the first analog-to-digital converter 501 are connected to the second acquisition channel 20 and the first acquisition channel 10 respectively, the first input terminal and the second input terminal of the second analog-to-digital converter 502 are connected to the first acquisition channel 10 and the second acquisition channel 20 respectively, and the first analog-to-digital converter 501 and the second analog-to-digital converter 502 are both connected to the microprocessor 40.

[0062] Since the polarities of the first acquisition channel 10 and the second acquisition channel 20 are opposite when the voltages of the odd-numbered batteries and the even-numbered batteries are collected, the voltages of the odd-numbered batteries and the even-numbered batteries are collected respectively by the first analog-to-digital converter 501 and the second analog-to-digital converter 502.

[0063] Specifically, Figure 4 As shown, when the voltage of the odd-numbered battery is collected, the first collection channel 10 is connected to the negative electrode of the battery, and the second collection channel 20 is connected to the positive electrode of the battery. At this time, the microprocessor 40 controls the first analog-to-digital converter 501 to collect the voltage of the odd-numbered battery; when the voltage of the even-numbered battery is collected, the first collection channel 10 is connected to the positive electrode of the battery, and the second collection channel 20 is connected to the negative electrode of the battery. At this time, the microprocessor 40 controls the second analog-to-digital converter 502 to collect the voltage of the odd-numbered battery.

[0064] The first analog-to-digital converter 501 and the second analog-to-digital converter 502 convert the collected voltage into digital signals and output them to the microprocessor 40 .

[0065] In practical applications, both the first analog-to-digital converter 501 and the second analog-to-digital converter 502 can adopt existing analog-to-digital converters. The specific models can be set according to actual conditions and are not limited here.

[0066] Figure 5 The circuit structure of a bipolar conversion unit in a voltage acquisition device provided by an embodiment of the present invention is shown. For the convenience of description, only the part related to the embodiment of the present invention is shown, which is described in detail as follows:

[0067] As an embodiment of the present invention, the polarity conversion unit 601 includes a first relay 610 , a second relay 620 , a third relay 630 and a fourth relay 640 .

[0068] The input end of the first relay 610 and the input end of the second relay 620 are connected together as the positive input end of the polarity conversion unit 601, the input end of the third relay 630 and the input end of the fourth relay 640 are connected together as the negative input end of the polarity conversion unit 601, the output end of the first relay 610 and the output end of the third relay 630 are connected together as the first output end of the polarity conversion unit 601, the output end of the second relay 620 and the output end of the fourth relay 640 are connected together as the second output end of the polarity conversion unit 601, and the controlled end of the first relay 610, the controlled end of the second relay 620, the controlled end of the third relay 630 and the controlled end of the fourth relay 640 are all connected to the microprocessor 40.

[0069] In the embodiment of the present invention, when charging an odd-numbered battery, the first acquisition channel 10 is connected to the negative electrode of the battery, and the second acquisition channel 20 is connected to the positive electrode of the battery. At this time, the microprocessor 40 controls the second relay 620 and the third relay 630 to open, and controls the first relay 610 and the fourth relay 640 to close, so as to connect the positive and negative electrodes of the power supply 602 to the positive and negative electrodes of the battery to be charged respectively; when charging an even-numbered battery, the first acquisition channel 10 is connected to the positive electrode of the battery, and the second acquisition channel 20 is connected to the negative electrode of the battery. At this time, the microprocessor 40 controls the first relay 610 and the fourth relay 640 to open, and controls the second relay 620 and the third relay 630 to close, so as to connect the positive and negative electrodes of the power supply 602 to the positive and negative electrodes of the battery to be charged respectively.

[0070] In the embodiment of the present invention, the first relay 610 , the second relay 620 , the third relay 630 , and the fourth relay 640 may all be existing relays.

[0071] The parameters of the power supply 620 can be set according to actual needs and are not limited here.

[0072] An embodiment of the present invention further provides a battery management system, which includes the voltage acquisition device in the above embodiment.

[0073] The voltage acquisition device provided in the embodiment of the present invention includes a first acquisition channel, a second acquisition channel, an acquisition channel control module, a microprocessor and an analog-to-digital conversion module. During the charging and discharging process of the power battery pack, the microprocessor outputs multiple control signals to the acquisition channel control module in a preset order; the acquisition channel control module controls the first acquisition channel and the second acquisition channel to connect the positive and negative electrodes of each battery to the analog-to-digital conversion module in a preset order according to the multiple control signals; the analog-to-digital conversion module acquires the voltage of each battery and outputs the acquisition result to the microprocessor, so that the microprocessor monitors the voltage of each battery. Since the voltage acquisition device acquires the voltage at both ends of each battery in a scanning manner one by one, the acquired voltage is within the standard voltage range, thereby improving the voltage acquisition accuracy of the voltage acquisition device.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A voltage acquisition device of a battery management system, connected to a power battery pack consisting of n batteries connected in series, where n is an integer greater than or equal to 2; the n batteries are connected in series from the first battery to the nth battery in a manner such that the negative electrode of the previous battery is connected to the positive electrode of the next battery; The voltage collection device is used to collect the voltage of each battery; it is characterized in that: The voltage acquisition device comprises: a first acquisition channel, a second acquisition channel, an acquisition channel control module, a microprocessor and an analog-to-digital conversion module; The first acquisition channel and the second acquisition channel are both connected to the acquisition channel control module and the analog-to-digital conversion module, and the microprocessor is connected to the acquisition channel control module and the analog-to-digital conversion module; During the charging and discharging process of the power battery pack, the microprocessor outputs a plurality of control signals to the acquisition channel control module in a preset order; the acquisition channel control module controls the first acquisition channel and the second acquisition channel to sequentially connect the positive electrode and the negative electrode of each battery to the analog-to-digital conversion module in a preset order according to the plurality of control signals; the analog-to-digital conversion module acquires the voltage of each battery and outputs the acquisition result to the microprocessor, so that the microprocessor monitors the voltage of each battery; The voltage collection device also includes a voltage equalization module; The voltage balancing module is connected to the first acquisition channel, the second acquisition channel and the microprocessor; after the power battery pack is charged and discharged, the microprocessor determines the voltage of each battery, and if the voltage of at least one of the n batteries is lower than the preset voltage threshold, the microprocessor outputs a corresponding balancing signal to the acquisition channel control module; the voltage balancing module charges the corresponding battery whose voltage is lower than the preset voltage threshold under the control of the microprocessor, so that the voltage of the corresponding battery whose voltage is lower than the preset voltage threshold is maintained within the preset voltage range; The acquisition channel control module includes a decoding unit and n+1 switch units; the decoding unit includes n+1 output terminals; The input end of the decoding unit is connected to the microprocessor, the first output end to the n+1th output end of the decoding unit are respectively connected to the first input end of the first switch unit to the first input end of the n+1th switch unit, the second input end of the n+1th switch unit is commonly connected to the ground, the first output end of the first switch unit to the first output end of the nth switch unit are respectively connected to the positive electrode of the first battery to the positive electrode of the nth battery, the first output end of the n+1th switch unit is connected to the negative electrode of the nth battery, the second output end of one of two adjacent switch units is connected to the first acquisition channel, and the second output end of the other switch unit is connected to the second acquisition channel; During the charging and discharging process of the power battery pack, the decoding unit decodes the multiple control signals output by the microprocessor, and outputs multiple sets of acquisition level information corresponding to the multiple control signals; the n+1 switch units control the first acquisition channel and the second acquisition channel to sequentially connect the positive and negative electrodes of the n batteries to the analog-to-digital conversion module in a preset order according to the multiple sets of acquisition level information, so that the analog-to-digital conversion module collects the voltage of each battery; After the power battery pack is charged and discharged, the decoding unit decodes the equalization signal output by the microprocessor, and outputs the equalization level information corresponding to the equalization signal; the n+1 switch units control the first acquisition channel and the second acquisition channel to connect the positive and negative electrodes of the corresponding batteries whose voltage is lower than the preset voltage threshold to the voltage equalization module according to the equalization level information, so that the voltage equalization module charges the corresponding batteries whose voltage is lower than the preset voltage threshold; The decoding unit decodes each control signal or each equalizing signal output by the microprocessor into two sets of level information, one set of level information is used to control the switch unit connected to the positive electrode of the target battery corresponding to the control signal or the equalizing signal so that the positive electrode of the target battery is connected to the second acquisition channel, and the other set of level information is used to control the switch unit connected to the negative electrode of the target battery corresponding to the control signal or the equalizing signal so that the negative electrode of the target battery is connected to the first acquisition channel.

2. The voltage acquisition device according to claim 1, characterized in that: The acquisition channel control module controls the first acquisition channel and the second acquisition channel to connect the positive electrode and the negative electrode of the corresponding battery whose voltage is lower than a preset voltage threshold to the voltage equalization module according to the equalization signal.

3. The voltage acquisition device according to claim 2, characterized in that: The voltage equalization module includes a power supply and a polarity conversion unit; the positive electrode and the negative electrode of the power supply are respectively connected to the positive input terminal and the negative input terminal of the polarity conversion unit, the first output terminal and the second output terminal of the polarity conversion unit are respectively connected to the first acquisition channel and the second acquisition channel, and the controlled terminal of the polarity conversion unit is connected to the microprocessor; The polarity conversion unit includes a first relay, a second relay, a third relay and a fourth relay; the input end of the first relay and the input end of the second relay are connected together as the positive input end of the polarity conversion unit, the input end of the third relay and the input end of the fourth relay are connected together as the negative input end of the polarity conversion unit, the output end of the first relay and the output end of the third relay are connected together as the first output end of the polarity conversion unit, the output end of the second relay and the output end of the fourth relay are connected together as the second output end of the polarity conversion unit, and the controlled end of the first relay, the controlled end of the second relay, the controlled end of the third relay and the controlled end of the fourth relay are all connected to the microprocessor.

4. The voltage acquisition device according to claim 3, characterized in that: When charging the battery whose corresponding voltage is lower than the preset voltage threshold, the polarity conversion unit connects the positive electrode and the negative electrode of the power source to the positive electrode and the negative electrode of the battery whose corresponding voltage is lower than the preset voltage threshold, respectively.

5. The voltage acquisition device according to claim 3, characterized in that: The switch unit is a photoelectric coupler; The first input terminal, the second input terminal, the first output terminal and the second output terminal of the photoelectric coupler are respectively the first input terminal, the second input terminal, the first output terminal and the second output terminal of the switch unit.

6. The voltage acquisition device according to claim 3, characterized in that: The decoding unit includes a first decoder and a second decoder; the first decoder and the second decoder each include an input terminal and n+1 output terminals; The input end of the first decoder and the input end of the second decoder constitute the input end of the decoding unit, the 1st output end to the n+1th output end of the first decoder are respectively connected to the 1st output end to the n+1th output end of the second decoder, and the 1st output end to the n+1th output end of the first decoder are respectively the 1st output end to the n+1th output end of the decoding unit.

7. The voltage acquisition device according to claim 1, characterized in that: The analog-to-digital conversion module includes a first analog-to-digital converter and a second analog-to-digital converter; The first input terminal and the second input terminal of the first analog-to-digital converter are connected to the second acquisition channel and the first acquisition channel respectively, the first input terminal and the second input terminal of the second analog-to-digital converter are connected to the first acquisition channel and the second acquisition channel respectively, and the first analog-to-digital converter and the second analog-to-digital converter are both connected to the microprocessor.

8. A battery management system, characterized in that: The battery management system comprises the voltage acquisition device according to any one of claims 1 to 7.

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