Testing device

Abstract

The utility model relates to a testing device, the testing device is applied to a battery pack, the battery pack comprises a positive electrode, a negative electrode and a battery shell, and the testing device is characterized by comprising a voltage acquisition unit, a first resistor, a second resistor, a third resistor and a fourth resistor; the first resistor and the third resistor are respectively connected between the negative electrode and the battery shell; and the second resistor and the fourth resistor are respectively connected between the positive electrode and the battery shell. According to the invention, by accessing different resistors, simultaneous testing of the insulation resistor and the Y capacitor is realized, the testing cost is saved, and the testing efficiency is improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a testing device. Background Art

[0002] Power batteries generally include multiple battery packs, each of which includes multiple batteries connected in series or in parallel. Due to the structural characteristics of the battery pack itself, there will be insulation resistance and parasitic Y capacitance between the electrodes of the battery pack and the battery pack shell. In order to ensure the safety of power batteries, it is generally necessary to conduct relevant safety tests on power batteries according to safety regulations, such as insulation tests, withstand voltage tests, Y capacitance tests, etc., to determine the safety of the battery pack based on the test results.

[0003] Insulation test and withstand voltage test can be directly performed by safety test equipment. However, the test of Y capacitor cannot be performed by safety test equipment, but requires special test equipment, which cannot be performed at the same time as insulation test, and the test efficiency is low. Utility Model Content

[0004] Based on this, it is necessary to provide a testing device to address the above technical issues.

[0005] In a first aspect, the present application provides a testing device, which is applied to a battery pack, wherein the battery pack includes a positive electrode, a negative electrode and a battery housing, and the testing device includes: a voltage acquisition unit, a first resistor, a second resistor, a third resistor and a fourth resistor;

[0006] The first resistor and the third resistor are used to be connected between the negative electrode and the battery housing respectively;

[0007] The second resistor and the fourth resistor are used to be connected between the positive electrode and the battery housing respectively;

[0008] The voltage acquisition unit is used to respectively acquire the first voltage and the second voltage between the negative electrode and the positive electrode and the battery case when the first resistor, the second resistor, the third resistor and the fourth resistor are not connected, and to respectively acquire the third voltage and the fourth voltage between the negative electrode and the positive electrode and the battery case when the third resistor or the fourth resistor is connected;

[0009] The voltage acquisition unit is further used to acquire a fifth voltage between the negative electrode and the battery case when the first resistor, the third resistor and the fourth resistor are connected, and to acquire a sixth voltage between the positive electrode and the battery case when the second resistor, the third resistor and the fourth resistor are connected;

[0010] Among them, the first voltage, the second voltage, the third voltage and the fourth voltage are used to obtain the insulation resistance between the negative electrode and the battery shell, and to obtain the insulation resistance between the positive electrode and the battery shell; the fifth voltage is used to obtain the Y capacitance between the negative electrode and the battery shell; the sixth voltage is used to obtain the Y capacitance between the positive electrode and the battery shell.

[0011] In a second aspect, a test device is provided, which is applied to a battery pack, wherein the battery pack includes a positive electrode, a negative electrode and a battery housing, and the test device includes: a voltage acquisition unit, a first resistor, a second resistor, a third resistor, a fourth resistor, a first switch, a second switch, a third switch and a fourth switch;

[0012] The first switch is connected in series with the first resistor and connected between the negative electrode and the battery housing; the second switch is connected in series with the second resistor and connected between the positive electrode and the battery housing; the third switch is connected in series with the third resistor and connected between the negative electrode and the battery housing; the fourth switch is connected in series with the fourth resistor and connected between the positive electrode and the battery housing;

[0013] The voltage acquisition unit is used to respectively acquire the first voltage and the second voltage between the negative electrode and the positive electrode and the battery case when the first switch, the second switch, the third switch and the fourth switch are not closed, and to respectively acquire the third voltage and the fourth voltage between the negative electrode and the positive electrode and the battery case when the third switch or the fourth switch is closed;

[0014] The voltage collection unit is further used to collect a fifth voltage between the negative electrode and the battery case when the first switch, the third switch and the fourth switch are closed, and to collect a sixth voltage between the positive electrode and the battery case when the second switch, the third switch and the fourth switch are closed;

[0015] Among them, the first voltage, the second voltage, the third voltage and the fourth voltage are used to obtain the insulation resistance between the negative electrode and the battery shell, and to obtain the insulation resistance between the positive electrode and the battery shell; the fifth voltage is used to obtain the Y capacitance between the negative electrode and the battery shell; the sixth voltage is used to obtain the Y capacitance between the positive electrode and the battery shell.

[0016] One of the above technical solutions has the following advantages and beneficial effects: by connecting different resistors, the insulation resistance and the Y capacitor can be tested simultaneously, thus saving the test cost and improving the test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a circuit diagram of a power battery according to an embodiment of the present application;

[0018] Figure 2 A structural block diagram of a testing device according to an embodiment of the present application;

[0019] Figure 3 A structural block diagram of a testing device according to another embodiment of the present application;

[0020] Figure 4 A structural block diagram of a testing device according to another embodiment of the present application;

[0021] Figure 5 This is a structural block diagram of a testing device according to another embodiment of the present application;

[0022] Figure 6 Schematic diagram of a test process of a test device according to an embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0024] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0025] In addition, the term "plurality" shall mean two and more than two. The term "exceeding" shall mean greater than or equal to.

[0026] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0027] See also Figure 1The power battery of the embodiment of the present application can be applied to energy storage equipment, electric vehicles, data centers and other equipment that require electricity.

[0028] In one embodiment of the present application, the power battery may include a plurality of battery packs 10 connected in series, each battery pack 10 including a battery housing 20 and a plurality of batteries connected in series placed in the battery housing. The battery housing is generally made of metal. Due to the structural characteristics of the battery pack, there is a parasitic capacitance (ie, Y capacitance) and insulation resistance between the battery electrodes and the battery housing 20. The insulation resistance is the equivalent resistance between the electrode and the battery housing.

[0029] Since the battery includes a positive electrode and a negative electrode, that is, a Y capacitor Cy- and an insulation resistor Ri- are included between the negative electrode and the battery case. A Y capacitor Cy+ and an insulation resistor Ri+ are included between the positive electrode of the battery pack and the battery case.

[0030] The testing device of the embodiment of the present application is used to test the Y capacitance and insulation resistance between the electrodes (including the positive electrode and the negative electrode) of the above-mentioned battery pack and the battery shell, that is, the testing device of the embodiment of the present application integrates the testing of Y capacitance and insulation resistance, improves the integration of the testing device, improves production efficiency, and saves testing costs.

[0031] See also Figure 2 It is a structural block diagram of a testing device according to an embodiment of the present application.

[0032] The testing device 30 according to an embodiment of the present application includes: a voltage acquisition unit 301 , a first resistor R1 , a second resistor R2 , a third resistor R3 , and a fourth resistor R4 .

[0033] The first resistor R1 and the third resistor R3 are used to be connected between the negative electrode and the battery housing 20, respectively; the second resistor R2 and the fourth resistor R4 are used to be connected between the positive electrode and the battery housing 20, respectively. That is, in the embodiment of the present application, the first resistor R1 and the third resistor R3 can be connected between the negative electrode and the battery housing 20, and can also be disconnected without connecting between the negative electrode and the battery housing 20. The second resistor R2 and the fourth resistor R4 can be connected between the positive electrode and the battery housing 20, and can also be disconnected without connecting between the positive electrode and the battery housing 20. In some embodiments, the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 can be connected to a switch, respectively, so as to realize the connection or disconnection of the resistor between the electrode and the battery housing 20 by controlling the closing and disconnection of the switch. The closing and disconnection of the switch can be controlled by a control module, for example, by outputting a signal through the control module to close and disconnect the switch.

[0034] The voltage acquisition unit 301 is used to respectively acquire the first voltage and the second voltage between the negative electrode and the positive electrode and the battery shell when the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 are not connected, and to respectively acquire the third voltage and the fourth voltage between the negative electrode and the positive electrode and the battery shell when the third resistor R3 or the fourth resistor R4 is connected.

[0035] The voltage collection unit 301 is also used to collect a fifth voltage between the negative electrode and the battery case when the first resistor R1, the third resistor R3 and the fourth resistor R4 are connected, and to collect a sixth voltage between the positive electrode and the battery case when the second resistor R2, the third resistor R3 and the fourth resistor R4 are connected.

[0036] Among them, the first voltage, the second voltage, the third voltage and the fourth voltage are used to obtain the insulation resistance between the negative electrode and the battery shell, and to obtain the insulation resistance between the positive electrode and the battery shell; the fifth voltage is used to obtain the Y capacitance between the negative electrode and the battery shell; the sixth voltage is used to obtain the Y capacitance between the positive electrode and the battery shell.

[0037] Therefore, the testing device of the embodiment of the present application realizes simultaneous testing of insulation resistance and Y capacitance by connecting different resistors, thereby saving testing costs and improving testing efficiency.

[0038] In one embodiment, when the first voltage is lower than the second voltage, the voltage acquisition unit 301 is used to respectively acquire a third voltage and a fourth voltage between the negative electrode and the positive electrode and the battery housing when the third resistor is connected;

[0039] When the second voltage is lower than the first voltage, the voltage acquisition unit 301 is used to respectively acquire a third voltage and a fourth voltage between the negative electrode and the positive electrode and the battery housing when the fourth resistor is connected.

[0040] That is, when all resistors are not connected, the voltage acquisition unit 301 acquires the first voltage on the negative electrode side and the second voltage on the positive electrode side. The side with a lower voltage value has a smaller insulation resistance value, which can be used as the insulation resistance R of the battery pack. i .

[0041] If the insulation resistance value on the negative electrode side is smaller (i.e., the first voltage is lower than the second voltage), the third resistor on the negative electrode side is connected, and the third voltage and the fourth voltage are collected again by the voltage collection unit 301. If the insulation resistance value on the positive electrode side is smaller (i.e., the second voltage is lower than the first voltage), the fourth resistor on the positive electrode side is connected, and the third voltage and the fourth voltage are collected again by the voltage collection unit 301.

[0042] In one embodiment, the insulation resistance R is obtained by formulas (1) and (2): i :

[0043]

[0044]

[0045] Among them, U 1a is the higher voltage of the first voltage and the second voltage, U 1b is the lower voltage of the first voltage and the second voltage, U 2a is the third voltage, U 2b is the fourth voltage, r is the internal resistance of the voltage acquisition unit, R 0 is the resistance value of the third resistor or the fourth resistor. As mentioned above, if the third resistor is connected, then R 0 is the resistance value of the third resistor; if the fourth resistor is connected, then R 0 is the resistance value of the fourth resistor.

[0046] In one embodiment, the third resistor R3 is a standard resistor disposed between the negative electrode and the battery housing, and its resistance value may be 1 MΩ. The fourth resistor R4 is a standard resistor disposed between the positive electrode and the battery housing, and its resistance value may be 1 MΩ.

[0047] In one embodiment, the first resistor R1 and the second resistor R2 are capacitor discharge resistors, and the resistance value of the resistor is one tenth of the standard resistor, for example, 100 kΩ.

[0048] In one embodiment, the insulation resistance R is obtained by formula (3): i ′:

[0049]

[0050] Among them, the insulation resistance R i And insulation resistance R i ′ are the positive and negative insulation resistances of the battery pack, or the insulation resistance R i And insulation resistance R i ' are the negative electrode insulation resistance and the positive electrode insulation resistance of the battery pack, respectively. That is, as mentioned above, if the insulation resistance value of the negative electrode side is smaller (that is, the first voltage is lower than the second voltage), the insulation resistance R i is the negative insulation resistance and the insulation resistance R i ' is the positive insulation resistance. If the insulation resistance value of the positive electrode side is smaller (that is, the second voltage is lower than the first voltage), the insulation resistance R i is the positive insulation resistance and insulation resistance R i ′ is the negative insulation resistance.

[0051] See also Figure 3In one embodiment of the present application, the testing device includes: a voltage acquisition unit 301, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first switch K1, a second switch K2, a third switch K3 and a fourth switch K4.

[0052] The voltage collection unit 301 is used to collect the first voltage and the second voltage between the negative electrode and the positive electrode and the battery shell respectively when the first switch K1, the second switch K2, the third switch K3 and the fourth switch K4 are not closed, and to collect the third voltage and the fourth voltage between the negative electrode and the positive electrode and the battery shell respectively when the third switch K3 or the fourth switch K4 is closed.

[0053] The voltage collection unit 301 is further used to collect a fifth voltage between the negative electrode and the battery case when the first switch K1, the third switch K3 and the fourth switch K4 are closed, and to collect a sixth voltage between the positive electrode and the battery case when the second switch K2, the third switch K3 and the fourth switch K4 are closed.

[0054] See also Figure 4 In a testing device of another embodiment of the present application, the voltage acquisition unit 301 includes: a first voltage acquisition unit V1 connected between the negative electrode and the battery housing and a second voltage acquisition unit V2 connected between the positive electrode and the battery housing.

[0055] The first voltage acquisition unit V1 is used to acquire the first voltage, the third voltage and the fifth voltage. The second voltage acquisition unit V2 is used to acquire the second voltage, the fourth voltage and the sixth voltage.

[0056] In one embodiment, the first voltage acquisition unit V1 and the second voltage acquisition unit V2 may be devices capable of voltage acquisition and recording, such as an oscilloscope. The first voltage acquisition unit V1 may have a certain equivalent resistance r1, and the second voltage acquisition unit V2 may have a certain equivalent resistance r2. The equivalent resistance r1 and the equivalent resistance r2 may be, for example, 10 MΩ.

[0057] In one embodiment, the Y capacitance Cy- between the negative electrode and the battery housing is obtained by formulas (5), (6) and (7):

[0058]

[0059]

[0060]

[0061] Wherein, R1 is the resistance value of the first resistor, R3 is the resistance value of the third resistor, R4 is the resistance value of the fourth resistor, r1 is the internal resistance of the first voltage acquisition unit, U1(t) is the curve function of the fifth voltage changing with time t, t 0 is the acquisition start time, t e is the acquisition end time, U1 0 is the voltage value of the fifth voltage at the beginning of the acquisition, U1 e is the voltage value of the fifth voltage at the end of acquisition.

[0062] In one embodiment, the Y capacitance Cy+ between the negative electrode and the battery housing is obtained by formulas (8), (9) and 10:

[0063]

[0064]

[0065]

[0066] Wherein, R2 is the resistance value of the second resistor, R3 is the resistance value of the third resistor, R4 is the resistance value of the fourth resistor, r2 is the internal resistance of the second voltage acquisition unit, U2(t) is the curve function of the sixth voltage changing with time t, t 0 is the acquisition start time, t e is the acquisition end time, U2 0 is the voltage value of the sixth voltage at the beginning of the acquisition, U2 e is the voltage value of the sixth voltage at the end of acquisition.

[0067] See also Figure 5 ,exist Figure 4 On the basis of the illustrated embodiment, in one embodiment of the present application, the testing device 30 further includes: a first switch K1, a second switch K2, a third switch K3 and a fourth switch K4. After the first switch K1 is connected in series with the first resistor R1, it is connected between the negative electrode and the battery housing, so that the first resistor R1 is connected between the negative electrode and the battery housing when the first switch K1 is closed. After the second switch K2 is connected in series with the second resistor R2, it is connected between the positive electrode and the battery housing, so that the second resistor R2 is connected between the positive electrode and the battery housing when the second switch K2 is closed. After the third switch K3 is connected in series with the third resistor R3, it is connected between the negative electrode and the battery housing, so that the third resistor R3 is connected between the negative electrode and the battery housing when the third switch K3 is closed. After the fourth switch K4 is connected in series with the fourth resistor R4, it is connected between the positive electrode and the battery housing, so that the fourth resistor R4 is connected between the positive electrode and the battery housing when the fourth switch K4 is closed.

[0068] The testing device 30 further includes: a fifth switch K5 and a sixth switch K6. The fifth switch K5 is connected to the first voltage acquisition unit V1 and the negative electrode respectively; the sixth switch K6 is connected to the second voltage acquisition unit V2 and the positive electrode respectively.

[0069] The following combination Figure 6 , a process of obtaining insulation resistance and Y capacitance by a testing device in one embodiment of the present application is described.

[0070] S1. Turn off all switches in the test device, that is, turn off the first switch K1, the second switch K2, the third switch K3, the fourth switch K4, the fifth switch K5 and the sixth switch K6. At this time, the test device is not connected.

[0071] S2, close the first switch K1 and the second switch K2, and collect the first voltage between the negative electrode and the battery case, and the second voltage between the positive electrode and the battery case through the first voltage acquisition unit V1 and the second voltage acquisition unit V2. Among them, the higher voltage is U1a, and the lower voltage is U1b. The insulation resistance value of the side with lower voltage is smaller, which is used as the insulation resistance Ri of the battery pack.

[0072] S3, closing the switch on the side with lower voltage connected to the standard resistor (ie, the third resistor R3 or the fourth resistor R4).

[0073] If the voltage on the negative electrode side is lower, the insulation resistance is lower, then the third switch K3 is closed. If the voltage on the positive electrode side is lower, the insulation resistance is lower, then the fourth switch K4 is closed. The voltage is collected again by the first voltage collection unit V1 and the second voltage collection unit V2, and the collected voltages are recorded as the third voltage U2a and the fourth voltage U2b respectively.

[0074] Therefore, the insulation resistance R can be obtained by the above formulas (1) and (2): i , the insulation resistance R can be obtained by the above formula (3) i '. When the first voltage is lower than the second voltage, the insulation resistance R i is the negative electrode insulation resistance; when the second voltage is lower than the first voltage, the insulation resistance R i is the positive electrode insulation resistance.

[0075] S4, close the first switch K1, the second switch K2, the third switch K3 and the fourth switch K4. It should be understood that in the above steps, if the corresponding switches are already closed, only the unclosed switches among the first switch K1, the second switch K2, the third switch K3 and the fourth switch K4 need to be closed.

[0076] S5. Close the fifth switch K5 to obtain the Y capacitor Cy- between the negative electrode and the battery housing.

[0077] When the fifth switch K5 is closed, the equivalent resistance Rn between the negative electrode and the battery housing (including the insulation resistance Ri-, the first resistor R1, the internal resistance r1 of the first voltage acquisition unit V1, and the third resistor R3) changes, causing the voltage of the Y capacitor to also change. The curve of the voltage changing with time t can be collected and recorded by the first voltage acquisition unit V1. The curve function of the voltage changing with time t is recorded as U1(t). Taking any time interval Δt, the voltage value U1 before the change can be obtained. 0 , the voltage value after the change is U1 e . The equivalent resistance Rn, time interval Δt, voltage value U1 0 And voltage value U1 e Substituting the above formula (5) and formula (6) into the total energy E1 in the time interval Δt, the Y capacitance Cy- between the negative electrode and the battery housing is calculated by the above formula (7).

[0078] In one embodiment of the present application, the first voltage acquisition unit V1 can acquire and record a voltage variation curve within a certain period of time, for example, a voltage variation curve within 10 seconds or 20 seconds. Any time interval Δt can be 1 millisecond, 2 milliseconds, etc.

[0079] S6, opening the fifth switch K5, and closing the sixth switch K6, so as to obtain the parasitic capacitance Cy+ between the positive electrode and the battery housing.

[0080] As with S5, when the sixth switch K6 is closed, the equivalent resistance Rp between the positive electrode and the battery housing (including the insulation resistance Ri+, the second resistor R2, the internal resistance r2 of the second voltage acquisition unit V2, and the fourth resistor R4) changes, causing the voltage of the Y capacitor to change. The curve of the voltage changing with time t can be collected and recorded by the second voltage acquisition unit V2. The curve function of the voltage changing with time t is recorded as U2(t). Taking any time interval Δt, the voltage value U2 before the change can be obtained. 0 , the voltage value after the change is U2 e . The equivalent resistance Rn, time interval Δt, voltage value U2 0 And voltage value U2 e Substituting the above formula (8) and formula (9) into the total energy E2 in the Δt time interval, the Y capacitance Cy+ between the negative electrode and the battery housing is calculated by the above formula (10).

[0081] The test device of the embodiment of the present application implements the test of the insulation resistance by first closing the first switch K1, the second switch K2, the third switch K3 and the fourth switch K4, and then implements the test of the Y capacitor by closing the fifth switch K5 and the sixth switch K6. Therefore, the test device of the embodiment of the present application can simultaneously implement the test of the insulation resistance and the Y capacitor, saving the test cost and improving the test efficiency.

[0082] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0083] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A testing device, applied to a battery pack, the battery pack comprising a positive electrode, a negative electrode and a battery housing, characterized in that: The testing device comprises: a voltage acquisition unit, a first resistor, a second resistor, a third resistor and a fourth resistor; The first resistor and the third resistor are used to be connected between the negative electrode and the battery housing respectively; The second resistor and the fourth resistor are used to be connected between the positive electrode and the battery housing respectively; The voltage acquisition unit is used to respectively acquire the first voltage and the second voltage between the negative electrode and the positive electrode and the battery case when the first resistor, the second resistor, the third resistor and the fourth resistor are not connected, and to respectively acquire the third voltage and the fourth voltage between the negative electrode and the positive electrode and the battery case when the third resistor or the fourth resistor is connected; The voltage acquisition unit is further used to acquire a fifth voltage between the negative electrode and the battery case when the first resistor, the third resistor and the fourth resistor are connected, and to acquire a sixth voltage between the positive electrode and the battery case when the second resistor, the third resistor and the fourth resistor are connected; Among them, the first voltage, the second voltage, the third voltage and the fourth voltage are used to obtain the insulation resistance between the negative electrode and the battery shell, and to obtain the insulation resistance between the positive electrode and the battery shell; the fifth voltage is used to obtain the Y capacitance between the negative electrode and the battery shell; the sixth voltage is used to obtain the Y capacitance between the positive electrode and the battery shell.

2. The testing device according to claim 1, characterized in that: When the first voltage is lower than the second voltage, the voltage acquisition unit is used to respectively acquire the third voltage and the fourth voltage between the negative electrode and the positive electrode and the battery housing when the third resistor is connected.

3. The testing device according to claim 1, characterized in that: When the second voltage is lower than the first voltage, the voltage acquisition unit is used to respectively acquire the third voltage and the fourth voltage between the negative electrode and the positive electrode and the battery housing when the fourth resistor is connected.

4. The testing device according to any one of claims 1 to 3, characterized in that: The testing device further includes: a first switch; The first switch is connected in series with the first resistor and is connected between the negative electrode and the battery housing, so that the first resistor is connected between the negative electrode and the battery housing when the first switch is closed.

5. The testing device according to any one of claims 1 to 3, characterized in that: The testing device further comprises: a second switch; The second switch is connected in series with the second resistor and is connected between the positive electrode and the battery housing, so that the second resistor is connected between the positive electrode and the battery housing when the second switch is closed.

6. The testing device according to any one of claims 1 to 3, characterized in that: The testing device further comprises: a third switch; The third switch is connected in series with the third resistor and is connected between the negative electrode and the battery housing, so that the third resistor is connected between the negative electrode and the battery housing when the third switch is closed.

7. The testing device according to any one of claims 1 to 3, characterized in that: The testing device further includes: a fourth switch; The fourth switch is connected in series with the fourth resistor and is connected between the positive electrode and the battery housing, so that the fourth resistor is connected between the positive electrode and the battery housing when the fourth switch is closed.

8. The testing device according to any one of claims 1 to 3, characterized in that: The voltage collection unit includes: a first voltage collection unit connected between the negative electrode and the battery housing and a second voltage collection unit connected between the positive electrode and the battery housing; The first voltage acquisition unit is used to acquire the first voltage, the third voltage and the fifth voltage; The second voltage acquisition unit is used to acquire the second voltage, the fourth voltage and the sixth voltage.

9. The testing device according to claim 8, characterized in that: The testing device further includes: a fifth switch and a sixth switch; The fifth switch is connected to the first voltage acquisition unit and the negative electrode respectively; The sixth switch is connected to the second voltage acquisition unit and the positive electrode respectively.

10. A testing device, applied to a battery pack, the battery pack comprising a positive electrode, a negative electrode and a battery casing, characterized in that: The testing device comprises: a voltage acquisition unit, a first resistor, a second resistor, a third resistor, a fourth resistor, a first switch, a second switch, a third switch and a fourth switch; The first switch is connected in series with the first resistor and connected between the negative electrode and the battery housing; the second switch is connected in series with the second resistor and connected between the positive electrode and the battery housing; the third switch is connected in series with the third resistor and connected between the negative electrode and the battery housing; the fourth switch is connected in series with the fourth resistor and connected between the positive electrode and the battery housing; The voltage acquisition unit is used to respectively acquire the first voltage and the second voltage between the negative electrode and the positive electrode and the battery case when the first switch, the second switch, the third switch and the fourth switch are not closed, and to respectively acquire the third voltage and the fourth voltage between the negative electrode and the positive electrode and the battery case when the third switch or the fourth switch is closed; The voltage collection unit is further used to collect a fifth voltage between the negative electrode and the battery case when the first switch, the third switch and the fourth switch are closed, and to collect a sixth voltage between the positive electrode and the battery case when the second switch, the third switch and the fourth switch are closed; Among them, the first voltage, the second voltage, the third voltage and the fourth voltage are used to obtain the insulation resistance between the negative electrode and the battery shell, and to obtain the insulation resistance between the positive electrode and the battery shell; the fifth voltage is used to obtain the Y capacitance between the negative electrode and the battery shell; the sixth voltage is used to obtain the Y capacitance between the positive electrode and the battery shell.

Images