CN212872820U - Current detection device and electric vehicle - Google Patents
Current detection device and electric vehicle Download PDFInfo
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- CN212872820U CN212872820U CN202021824008.7U CN202021824008U CN212872820U CN 212872820 U CN212872820 U CN 212872820U CN 202021824008 U CN202021824008 U CN 202021824008U CN 212872820 U CN212872820 U CN 212872820U
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- Y02T10/70—Energy storage systems for electromobility, e.g. batteries
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Abstract
The embodiment of the utility model discloses a current detection device and an electric vehicle, wherein the current detection device comprises a first sampling module, a second sampling module and a control module; the first sampling module comprises a first sampling resistor and a first switch unit; the second sampling module comprises a second sampling resistor, a second switch unit and a second voltage acquisition unit; the second voltage acquisition unit is used for acquiring voltages at two ends of the second sampling resistor; when the control module detects that the current passing through the first sampling module is smaller than a set threshold value, the first switch unit is disconnected, the second switch unit is connected, and the current power supply current of the battery pack is obtained through the second voltage acquisition unit. According to the scheme, when the current of the whole vehicle is detected to be small, the current supply current of the battery pack is determined through the voltages at the two ends of the second sampling resistor, so that the cost is reduced, and the detection precision of the small current is improved.
Description
Technical Field
The embodiment of the utility model provides a relate to and detect technical field, especially relate to a current detection device and electric motor car.
Background
At present, global climate is warming and environmental pollution tends to be serious, and the nation advocates the development of electric vehicles vigorously. Lithium batteries are increasingly widely used in electric vehicles due to advantages of high energy density, environmental protection, light weight, and the like. In order to ensure the safe use of the lithium battery, the remaining capacity of the lithium battery is generally monitored and managed.
When the electric vehicle is in a key-off state, the lithium battery is required to be in a constant output power supply state in a vehicle-mounted state because devices such as an alarm and the like on the vehicle need to be in a working state all the time. In order to correctly estimate the remaining battery capacity (SOC) Of the lithium battery, the power consumption current Of the entire vehicle in the key-off State needs to be detected.
The traditional current detection device has high accuracy in the key-on state, and has low accuracy in the key-off state, so that the estimation result of the residual electric quantity of the lithium battery is influenced.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model provides a current detection device and electric motor car when whole car electric current is less, promote group battery supply current's detection precision.
In a first aspect, an embodiment of the present invention provides a current detection device for detecting a supply current of a battery pack, where the current detection device includes a first sampling module, a second sampling module, and a control module;
the first sampling module comprises a first sampling resistor and a first switch unit; the second sampling module comprises a second sampling resistor, a second switch unit and a second voltage acquisition unit;
the negative electrode of the battery pack is connected with the positive electrode of the battery pack sequentially through the first switch unit, the first sampling resistor and the load, the negative electrode of the battery pack is further connected with the positive electrode of the battery pack sequentially through the second switch unit, the second sampling resistor and the load, the first input end and the second input end of the second voltage acquisition unit are respectively connected with two ends of the second sampling resistor, and the output end of the second voltage acquisition unit is connected with the control module;
when the control module detects that the current passing through the first sampling module is smaller than a set threshold value, the first switch unit is disconnected, the second switch unit is connected, and the current supply current of the battery pack is acquired through the second voltage acquisition unit.
Optionally, the first sampling resistor is a milliohm-level resistor, and the second sampling resistor is an ohm-level resistor.
Optionally, the second sampling module further includes a current-limiting resistor, one end of the current-limiting resistor is connected to the second sampling resistor, and the other end of the current-limiting resistor is connected to the load.
Optionally, the first sampling module further includes an operational amplification unit and a signal conversion unit;
a first input end and a second input end of the operational amplification unit are respectively connected with two ends of the first sampling resistor, and an output end of the operational amplification unit is connected with the control module through the signal conversion unit;
when the control module detects that a key of a vehicle corresponding to the battery pack is in an opening state, the second switch unit is disconnected, the first switch unit is connected, and the current power supply current of the battery pack is obtained through the signal conversion unit.
Optionally, the first switch unit is an N-type MOS transistor.
Optionally, the second switch unit is an N-type MOS transistor.
Optionally, the control module is a single chip microcomputer.
In a second aspect, an embodiment of the present invention provides an electric vehicle, which includes a battery pack, a key door, a load, and a current detection device as described in the first aspect.
The embodiment of the utility model provides a current detection device and electric motor car, including first sampling module, second sampling module and control module; the first sampling module comprises a first sampling resistor and a first switch unit; the second sampling module comprises a second sampling resistor, a second switch unit and a second voltage acquisition unit; the negative electrode of the battery pack is connected with the positive electrode of the battery pack sequentially through the first switch unit, the first sampling resistor and the load, the negative electrode of the battery pack is further connected with the positive electrode of the battery pack sequentially through the second switch unit, the second sampling resistor and the load, the first input end and the second input end of the second voltage acquisition unit are respectively connected with two ends of the second sampling resistor, and the output end of the second voltage acquisition unit is connected with the control module; when the control module detects that the current passing through the first sampling module is smaller than a set threshold value, the first switch unit is disconnected, the second switch unit is connected, and the current power supply current of the battery pack is obtained through the second voltage acquisition unit. According to the scheme, when the current of the whole vehicle is detected to be small, the current supply current of the battery pack is determined through the voltages at the two ends of the second sampling resistor, so that the cost is reduced, and the detection precision of the small current is improved.
Drawings
Fig. 1 is a structural diagram of a current detection device according to an embodiment of the present invention;
fig. 2 is a structural diagram of another current detection device according to an embodiment of the present invention;
fig. 3 is a schematic view of a partial structure of an electric vehicle according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures. Furthermore, the embodiments and features of the embodiments of the present invention may be combined with each other without conflict.
Fig. 1 is the embodiment of the utility model provides a pair of current detection device's structure chart, the device are applicable to the supply current who detects group battery in the electric motor car, and when especially the electric motor car key was closed, whole car is power consumptive less, is in the mA rank usually, can improve the detection precision of undercurrent through this scheme, and then when the residual capacity of estimation group battery, improve the degree of accuracy of estimation result, guarantee the safe handling of group battery. The electric vehicle can be a two-wheel electric vehicle or a four-wheel electric vehicle, and the battery pack can be a lithium battery pack so as to meet the light weight requirement of the whole vehicle of a user.
Referring to fig. 1, the current detection apparatus 1 includes a first sampling module 11, a second sampling module 12, and a control module 13; the first sampling module 11 includes a first sampling resistor 110 and a first switching unit 111; the second sampling module 12 includes a second sampling resistor 120, a second switching unit 121, and a second voltage collecting unit 122;
the negative electrode of the battery pack 2 is connected with the positive electrode of the battery pack 2 sequentially through the first switch unit 111, the first sampling resistor 110 and the load 3, the negative electrode of the battery pack 2 is further connected with the positive electrode of the battery pack 2 sequentially through the second switch unit 121, the second sampling resistor 120 and the load 3, the first input end A and the second input end B of the second voltage acquisition unit 122 are respectively connected with two ends of the second sampling resistor 120, and the output end C of the second voltage acquisition unit 122 is connected with the control module 13;
when the control module 13 detects that the current passing through the first sampling module 11 is smaller than the set threshold, the first switch unit 111 is turned off, the second switch unit 121 is turned on, and the current supply current of the battery pack 2 is acquired through the second voltage acquisition unit 122.
The first sampling module 11 of this embodiment is used to detect the supply current of the battery pack 2 when the current of the entire vehicle is large, for example, the first sampling module may be used to detect the supply current of the battery pack 2 when the electric vehicle key is in an on state. The second sampling module 12 is configured to detect a supply current of the battery pack 2 when the vehicle current is small, for example, the supply current of the battery pack 2 when the electric vehicle key is in an off state may be detected. In order to detect the supply current of the battery pack 2 in different states of the key, the first sampling module 11 includes a first sampling resistor 110 and a first switching unit 111, and the second sampling module 12 includes a second sampling resistor 120, a second switching unit 121, and a second voltage collecting unit 122. The first switch unit 111 and the second switch unit 121 may be the same type of switch unit or different types of switch units, and the first switch unit 111 and the second switch unit 121 may be automatically turned on or off under the control of the control module 13 without manual control. Considering that a process is usually required for the change of the current, when the control module 13 detects that the key is in the off state and the current is less than the set threshold, the second switch unit 121 is controlled to be turned on and the first switch unit 111 is turned off. When the control module 13 detects that the key is in the on state and the current is greater than or equal to the set threshold, the second switch unit 121 is controlled to be turned off, and the first switch unit 111 is turned on, so that the current detection in different states is realized. The size of the set threshold can be set according to actual needs, and can be set to 70mA, for example. The load 3 may comprise an alarm or the like.
Considering that the supply current of the battery pack 2 is greater when the key is in the on state than when the key is in the off state, in order to improve the detection precision of the small current and further improve the estimation accuracy of the remaining power of the battery pack 2, the second sampling resistor 120 of the embodiment may be an ohm-level resistor, and the first sampling resistor 110 may be a milliohm-level resistor. The second voltage collecting unit 122 collects the voltages at the two ends of the second sampling resistor 120, so that the control module 13 obtains the current power supply current of the battery pack 2 according to the voltages collected by the second voltage collecting unit 122, an operational amplifying unit and a signal converting unit are not needed, and the cost is reduced while the small current detection precision is improved. The resistance of the second sampling resistor 120 may be determined according to actual conditions, and may be 1 ohm, for example.
The embodiment of the utility model provides a current detection device, including first sampling module, second sampling module and control module; the first sampling module comprises a first sampling resistor and a first switch unit; the second sampling module comprises a second sampling resistor, a second switch unit and a second voltage acquisition unit; the negative electrode of the battery pack is connected with the positive electrode of the battery pack sequentially through the first switch unit, the first sampling resistor and the load, the negative electrode of the battery pack is further connected with the positive electrode of the battery pack sequentially through the second switch unit, the second sampling resistor and the load, the first input end and the second input end of the second voltage acquisition unit are respectively connected with two ends of the second sampling resistor, and the output end of the second voltage acquisition unit is connected with the control module; when the control module detects that the current passing through the first sampling module is smaller than a set threshold value, the first switch unit is disconnected, the second switch unit is connected, and the current power supply current of the battery pack is obtained through the second voltage acquisition unit. According to the scheme, when the current of the whole vehicle is detected to be small, the current supply current of the battery pack is determined through the voltages at the two ends of the second sampling resistor, so that the cost is reduced, and the detection precision of the small current is improved.
On the basis of the above embodiment, the first sampling resistor 110 is a milliohm resistor, and the second sampling resistor 120 is an ohm resistor. Therefore, when the current of the whole vehicle is detected to be smaller than the set threshold value, the current power supply current of the battery pack 2 can be acquired through the second voltage acquisition units 122 at the two ends of the ohm-level resistor, so that the cost is reduced, and the detection precision of the small current is improved.
Fig. 2 is a structural diagram of another current detection device according to an embodiment of the present invention, referring to fig. 2 on the basis of the above embodiment, the second sampling module 12 further includes a current limiting resistor 123, one end of the current limiting resistor 123 is connected to the second sampling resistor 120, and the other end of the current limiting resistor 123 is connected to the load 3.
The resistance of the current limiting resistor 123 can be selected according to actual needs, and the current limiting resistor 123 is used for limiting the charging current of the load 3.
On the basis of the above embodiment, referring to fig. 2, the first sampling module 11 further includes an operational amplification unit 112 and a signal conversion unit 113;
a first input end D and a second input end E of the operational amplification unit 112 are respectively connected with two ends of the first sampling resistor 110, and an output end F of the operational amplification unit 112 is connected with the control module 13 through a signal conversion unit 113;
when the control module 13 detects that the key of the vehicle corresponding to the battery pack 2 is in the on state and the vehicle current is greater than the set threshold, the second switch unit 121 is turned off, the first switch unit 111 is turned on, and the current power supply current of the battery pack 2 is obtained through the signal conversion unit 113.
The operational amplifier unit 112 is configured to amplify the sampled voltage at two ends of the first sampling resistor 110, and the signal converter unit 113 is configured to convert the analog voltage signal into a digital voltage signal and transmit the digital voltage signal to the control module 13, so that the control module 13 determines the current power supply current of the battery pack 2 according to the digital voltage signal. Specifically, when the control module 13 detects that the key is in the on state and the vehicle current is greater than the set threshold, the first switch unit 111 is turned on and the second switch unit 121 is turned off, and the current power supply current of the battery pack 2 is obtained according to the digital voltage signal sent by the signal conversion unit 113. Since the supply current of the battery pack 2 is large when the key is turned on, in order to reduce the consumption of the first sampling resistor 110, in the present embodiment, a resistor of a milliohm level is selected, and in order to consider the current detection accuracy in this state, the present embodiment amplifies the sampling voltage of the first sampling resistor 110 by using the operational amplifier unit 112, thereby reducing the power consumption and improving the current detection accuracy.
On the basis of the above embodiment, the first switch unit 111 is an N-type MOS transistor; the second switch unit 121 is an N-type MOS transistor.
The first switch unit 111 and the second switch unit 121 of the present embodiment are exemplified by the same type, and select N-type MOS transistors, which is low in cost and can be cut off with electricity. For example, in a case where the first switching unit 111 is turned on and the second switching unit 121 is turned off, if the current is detected to be less than the set threshold, the second switching unit 121 is turned on and the first switching unit 111 is turned off, whereas if the current is detected to be greater than the set threshold in a state where the first switching unit 111 is turned off and the second switching unit 121 is turned on, the first switching unit 111 is turned on and the second switching unit 121 is turned off.
On the basis of the above embodiment, the control module 13 is a single chip microcomputer.
The control module 13 of this embodiment is exemplified by a single chip microcomputer in a Micro Controller Unit (MCU). The ratio of the resolution of the voltage drop collected by the single chip microcomputer to the voltage drop generated at the two ends of the second sampling resistor 120The relationship may be adjusted according to the application scenario. For example, when the key is turned off, the power consumption current of the whole vehicle is usually 20mA, the voltage flowing through the second sampling resistor 120 is 20mv assuming that the resistance value of the second sampling resistor 120 is 1 ohm, and the resolution of the voltage drop collected by the single chip microcomputer is 5/2 if the single chip microcomputer adopts 5V power supply and is provided with a 12-bit ADC12And 1mv, the voltage drop brought by the second sampling resistor 120 and the voltage drop collected by the singlechip are in a 1:1 relationship.
The embodiment of the utility model provides a solve the key through lower cost and closed, the detection precision of electric current under the undercurrent state, and then promoted the precision of the SOC under the or undercurrent state of stewing, promoted the price competitive advantage of whole car system.
Fig. 3 is a schematic view of a partial structure of an electric vehicle according to an embodiment of the present invention. The electric vehicle comprises a battery pack 2, a key door 4, a load 3 and the current detection device 1 as described in the above embodiment, wherein the cathode of the battery pack 2 sequentially passes through a first switch unit 111, a first sampling resistor 110, and the load 3 is connected with the anode of the battery pack 2, two input ends of an operational amplification unit 112 are respectively connected with the first sampling resistor 110, the output end of the operational amplification unit 112 is connected with a single chip microcomputer 13 through a signal conversion unit 113, the cathode of the battery pack 2 sequentially passes through a second switch unit 121, a second sampling resistor 120, a current limiting resistor 123, and the load 3 and is connected with the anode of the battery pack 2, two input ends of a second voltage acquisition unit 122 are respectively connected with two ends of the second sampling resistor 120, and the output end of the second voltage acquisition unit 122 is connected with the single chip microcomputer 13. The single chip microcomputer 13 is connected with the key door 4, and the use state of the key can be obtained through the key door 4.
When the key is in different states and the current of the whole vehicle meets set conditions, the corresponding switch units can be controlled to be switched on or switched off respectively, the power supply current of the battery pack 2 in different states can be detected, the accuracy of the SOC estimation result is improved, and the cost is low.
It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.
Claims (8)
1. The current detection device is used for detecting the supply current of a battery pack and comprises a first sampling module, a second sampling module and a control module;
the first sampling module comprises a first sampling resistor and a first switch unit; the second sampling module comprises a second sampling resistor, a second switch unit and a second voltage acquisition unit;
the negative electrode of the battery pack is connected with the positive electrode of the battery pack sequentially through the first switch unit, the first sampling resistor and the load, the negative electrode of the battery pack is further connected with the positive electrode of the battery pack sequentially through the second switch unit, the second sampling resistor and the load, the first input end and the second input end of the second voltage acquisition unit are respectively connected with two ends of the second sampling resistor, and the output end of the second voltage acquisition unit is connected with the control module;
when the control module detects that the current passing through the first sampling module is smaller than a set threshold value, the first switch unit is disconnected, the second switch unit is connected, and the current supply current of the battery pack is acquired through the second voltage acquisition unit.
2. The current sensing device of claim 1, wherein the first sampling resistor is a milliohm resistor and the second sampling resistor is an ohm resistor.
3. The current detection device according to claim 1, wherein the second sampling module further comprises a current limiting resistor, one end of the current limiting resistor is connected to the second sampling resistor, and the other end of the current limiting resistor is connected to the load.
4. The current detection device according to any one of claims 1 to 3, wherein the first sampling module further comprises an operational amplification unit and a signal conversion unit;
a first input end and a second input end of the operational amplification unit are respectively connected with two ends of the first sampling resistor, and an output end of the operational amplification unit is connected with the control module through the signal conversion unit;
when the control module detects that a key of a vehicle corresponding to the battery pack is in an opening state, the second switch unit is disconnected, the first switch unit is connected, and the current power supply current of the battery pack is obtained through the signal conversion unit.
5. The current detecting device according to any one of claims 1 to 3, wherein the first switching unit is an N-type MOS transistor.
6. The current detecting device according to any one of claims 1 to 3, wherein the second switching unit is an N-type MOS transistor.
7. The current detection device according to any one of claims 1 to 3, wherein the control module is a single chip microcomputer.
8. An electric vehicle comprising a battery pack, a key door, a load, and the current detection device according to any one of claims 1 to 7.
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| CN202021824008.7U CN212872820U (en) | 2020-08-27 | 2020-08-27 | Current detection device and electric vehicle |
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| CN202021824008.7U CN212872820U (en) | 2020-08-27 | 2020-08-27 | Current detection device and electric vehicle |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115993478A (en) * | 2023-03-21 | 2023-04-21 | 海的电子科技(苏州)有限公司 | Current detection circuit, current detection method and electronic equipment |
| WO2024183285A1 (en) * | 2023-03-09 | 2024-09-12 | 上汽通用五菱汽车股份有限公司 | Method for determining state of charge of power battery, and related device |
-
2020
- 2020-08-27 CN CN202021824008.7U patent/CN212872820U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024183285A1 (en) * | 2023-03-09 | 2024-09-12 | 上汽通用五菱汽车股份有限公司 | Method for determining state of charge of power battery, and related device |
| CN115993478A (en) * | 2023-03-21 | 2023-04-21 | 海的电子科技(苏州)有限公司 | Current detection circuit, current detection method and electronic equipment |
| CN115993478B (en) * | 2023-03-21 | 2023-05-16 | 海的电子科技(苏州)有限公司 | Current detection circuit, current detection method and electronic equipment |
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