Switching device for switching series-parallel connection states of battery pack modules

Abstract

The utility model provides a switching device for switching series-parallel connection states of battery pack modules, which relates to the technical field of new energy automobiles and comprises a controller, an actuator, a first battery pack and a second battery pack. The input end of the controller is electrically connected with electrical equipment, the output end of the controller is electrically connected with the input end of the actuator, and the output end of the actuator is fixedly connected with a connecting rod; the actuator controls the connecting rod to drive the first battery pack and the second battery pack to be connected in parallel or in series according to signals of the controller, and the first battery pack and the second battery pack are electrically connected with an electric vehicle load or charging equipment after being connected in parallel or in series. The controller controls the actuator to act, rapid series-parallel connection state switching of the two battery packs is achieved, the battery packs can be in a series connection high-voltage state and a parallel connection low-voltage state, and the adaptive working condition of rapid charging of the electric vehicle battery packs is expanded.

Description

Technical Field

[0001] The utility model relates to the technical field of new energy electric vehicles and electronic appliances, and in particular to a switch device for switching the series-parallel state of a battery pack module. Background Art

[0002] As the concept of energy conservation and environmental protection has become deeply rooted in people's hearts, the electrification of automobiles has become an irreversible trend, and the new energy automobile industry has entered the fast lane of development. The development of the new energy automobile industry has been greatly promoted by technological progress. The progress of power battery technology has made up for the endurance gap. The current technical level of electric vehicles and the voltage level of battery packs are generally in the 400V range. However, the traditional electric vehicle charging time is long, which has gradually become one of the obstacles to the rapid popularization of electric vehicles. Users' demand for charging speed is growing, so 800V high-voltage fast charging technology came into being, aiming to achieve fast charging, shorten charging and energy replenishment time, and improve user experience. An effective way to shorten charging time and increase charging rate is to increase charging power.

[0003] One way to increase the charging power is to increase the charging current on the existing 400V voltage battery pack platform. However, the power loss of the charging line, that is, the heat power, is proportional to the square of the charging current. The increase in charging current will cause a significant increase in the power loss from the charging device through the charging cable to the battery pack, that is, the heat power of the entire line will increase significantly. This method increases the charging current while reducing the heat power. It is necessary to reduce the resistance value of the entire charging circuit. The charging equipment needs to be replaced with higher specification connectors and use thicker diameter charging cables. This not only increases the construction cost, but also makes the overly thick and heavy charging cables very inconvenient to use.

[0004] Another way to increase the charging power is to increase the charging voltage, such as using 800V fast charging. This method can double the charging power without increasing the charging current. Because this method does not increase the charging current, the power loss of the entire charging circuit, that is, the heat power, will not increase. At the same time, there is no need to replace the connector with a larger specification and a thicker cable, so the charging power will not increase the charging power loss while increasing the charging power, and the charging equipment does not need to be replaced with a larger diameter charging cable.

[0005] Compared with 400V low voltage, electric vehicles have many advantages in using 800V battery pack systems. However, the 400V battery pack platform and 800V battery pack platform coexist in the electric vehicle market, and there will be a mismatch between the vehicle battery system voltage and the charging equipment voltage. This situation will restrict the high voltage process of electric vehicles and reduce the user experience.

[0006] In order to solve this problem, existing electric vehicle manufacturers have provided the following solutions: The first solution is to add a DC / DC charging voltage conversion device inside the vehicle so that the vehicle can accept two different charging voltages of 400V or 800V. However, this solution not only increases the manufacturing cost of the vehicle, but also reduces the charging power when using compatible charging equipment, and cannot achieve fast charging on compatible charging equipment; another solution is to use a relay array to form a battery module series and parallel switching circuit inside the vehicle battery pack to achieve high and low voltage switching to adapt to fast charging equipment with different voltages. However, this solution adds a large number of high-voltage relays, and the increase in the number of parts makes the battery pack system more complicated, which increases the manufacturing cost of the vehicle and increases the number of possible failure points in the vehicle system. Summary of the invention

[0007] The technical problem to be solved by the present invention is that in the prior art, in order to achieve matching of the voltage of an electric vehicle battery pack with the voltage of a charging device, the circuit system connection is complex. In order to overcome the above defects of the prior art, the present invention provides a switch device for switching the series-parallel state of a battery pack module.

[0008] The utility model provides a switch device for switching the series-parallel state of a battery pack module, comprising a controller, an actuator, a first battery group and a second battery group; the input end of the controller is electrically connected to an electrical device, the output end of the controller is electrically connected to an input end of the actuator, and the output end of the actuator is fixedly connected to a connecting rod; the actuator controls the connecting rod to drive the first battery group and the second battery group to be connected in parallel or in series according to a signal from the controller, and the first battery group and the second battery group are electrically connected to an electric vehicle load or a charging device after being connected in parallel or in series.

[0009] Compared with the prior art, the switch device for switching the series-parallel state of a battery pack module in the present application has the following advantages: the controller controls the action of the actuator to realize the rapid series-parallel state switching of the two battery packs. When the battery pack is in a series high-voltage state, the battery pack can accept high-voltage rapid charging, or can drive a high-voltage load; when the battery pack is in a parallel low-voltage state, the battery pack can accept low-voltage compatible charging, or can drive a low-voltage load; the battery pack can be placed in a series high-voltage state and a parallel low-voltage state respectively, expanding the adaptability of the battery pack for rapid charging of electric vehicles.

[0010] In a possible implementation, the positive electrode of the first battery pack is electrically connected to the first positive electrode connecting sheet, the negative electrode of the first battery pack is electrically connected to the first negative electrode connecting sheet, the positive electrode of the second battery pack is electrically connected to the second positive electrode connecting sheet, and the negative electrode of the second battery pack is electrically connected to the second negative electrode connecting sheet;

[0011] The second positive electrode connecting piece is disposed between the first positive electrode connecting piece and the first negative electrode connecting piece, the second negative electrode connecting piece is disposed at an end of the first negative electrode connecting piece away from the second positive electrode connecting piece, and the connecting rod is fixedly connected to the first positive electrode connecting piece and the first negative electrode connecting piece;

[0012] The actuator controls the connecting rod to electrically connect the first positive electrode connecting plate with the second positive electrode connecting plate and the first negative electrode connecting plate according to the signal of the controller; or the actuator controls the connecting rod to electrically connect the first negative electrode connecting plate with the second positive electrode connecting plate according to the signal of the controller.

[0013] Compared with the prior art, connecting pieces are led out from both ends of the positive and negative electrodes of the two battery packs, which facilitates the connecting rod to drive the connecting piece to move, thereby controlling the two battery packs to be connected in series or in parallel.

[0014] In a possible implementation manner, the first positive electrode connecting sheet and the first negative electrode connecting sheet are flexible conductive sheets, and the second positive electrode connecting sheet and the second negative electrode connecting sheet are rigid conductive sheets.

[0015] Compared with the prior art, the connecting rod drives the first positive electrode connecting plate and the first negative electrode connecting plate to move, and the two connecting plates are set to a flexible conductive plate structure for easy movement; and the second positive electrode connecting plate and the second negative electrode connecting plate serve as the connected ends, and by setting them to a rigid conductive plate structure, the position is ensured not to be shifted, thereby ensuring the stability of the connection.

[0016] In a possible implementation, a first conductive moving contact is provided at the end of the first positive electrode connecting sheet close to the second positive electrode connecting sheet, and a second conductive moving contact is provided at the end of the first negative electrode connecting sheet close to the second positive electrode connecting sheet and close to the second negative electrode connecting sheet.

[0017] Compared with the prior art, by providing a conductive moving contact, electrical connection can be performed in advance, thereby preventing the connection sheet from being deformed due to long-term use and causing unstable connection.

[0018] In a possible implementation, a first conductive static contact is provided at the second positive electrode connecting piece below the end of the first positive electrode connecting piece, a second conductive static contact is provided at the second positive electrode connecting piece above the end of the first negative electrode connecting piece, and a third conductive static contact is provided at the second negative electrode connecting piece below the end of the first negative electrode connecting piece.

[0019] Compared with the prior art, the conductive static contact is added to ensure that the connecting piece has a better connection end and is convenient for connection.

[0020] In a possible implementation, the second positive electrode connecting sheet includes a first conductive sheet disposed on a side close to the first positive electrode connecting sheet, a second conductive sheet disposed on a side close to the second negative electrode connecting sheet, and a third conductive sheet for electrically connecting the first conductive sheet and the second conductive sheet;

[0021] The first conductive sheet and the third conductive sheet are vertically fixedly connected, the third conductive sheet and the second conductive sheet are vertically fixedly connected, the first conductive sheet is electrically connected to the positive electrode of the second battery pack, the first conductive static contact is arranged on the first conductive sheet, and the second conductive static contact is arranged on the second conductive sheet.

[0022] Compared with the prior art, the second positive electrode connecting plate is split into three conductive plates, which is convenient for installation, ensures sufficient safety distance between the positive and negative electrodes, and facilitates the installation of two battery packs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of a switch device for switching the series and parallel states of a battery pack module according to the utility model;

[0024] Figure 2 This is a schematic diagram of the series connection structure of a switch device for switching the series-parallel connection state of a battery pack module according to the utility model;

[0025] Figure 3 The utility model is a schematic diagram of the parallel state structure of a switch device for switching the series and parallel states of battery pack modules.

[0026] Description of reference numerals:

[0027] 1- Controller;

[0028] 2-actuator; 21-connecting rod;

[0029] 3-first battery pack; 31-first positive electrode connecting piece; 311-first conductive moving contact; 32-first negative electrode connecting piece; 321-second conductive moving contact;

[0030] 4-second battery pack; 41-second positive electrode connecting piece; 411-first conductive static contact; 412-second conductive static contact; 42-second negative electrode connecting piece; 421-third conductive static contact;

[0031] 51 - first conductive sheet; 52 - second conductive sheet; 53 - third conductive sheet. DETAILED DESCRIPTION

[0032] First, those skilled in the art should understand that these implementations are only used to explain the technical principles of the embodiments of the present application, and are not intended to limit the protection scope of the embodiments of the present application. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0033] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0034] In the embodiments of the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0035] The present application is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] See also Figure 1 to Figure 3 As shown, an embodiment of the present application discloses a switch device for switching the series-parallel state of a battery pack module, including a controller 1, an actuator 2, a first battery group 3 and a second battery group 4.

[0037] The input end of the controller 1 is electrically connected to the electrical equipment, the output end of the controller 1 is electrically connected to the input end of the actuator 2, and the output end of the actuator 2 is fixedly connected to a connecting rod 21; the actuator 2 controls the connecting rod 21 to drive the first battery group 3 and the second battery group 4 to be connected in parallel or in series according to the signal of the controller 1, and the first battery group 3 and the second battery group 4 are electrically connected to the electric vehicle load or charging equipment after being connected in parallel or in series.

[0038] The controller 1 controls the actuator 2 to switch the two battery packs in series and parallel quickly. When the battery pack is in the series high voltage state, the battery pack can accept high voltage fast charging or drive high voltage loads; when the battery pack is in the parallel low voltage state, the battery pack can accept low voltage compatible charging or drive low voltage loads. The battery pack can be placed in the series high voltage state and the parallel low voltage state, expanding the adaptability of electric vehicle battery packs to fast charging.

[0039] In this embodiment, the positive electrode of the first battery group 3 is electrically connected to the first positive electrode connecting plate 31, the negative electrode of the first battery group 3 is electrically connected to the first negative electrode connecting plate 32, the positive electrode of the second battery group 4 is electrically connected to the second positive electrode connecting plate 41, and the negative electrode of the second battery group 4 is electrically connected to the second negative electrode connecting plate 42.

[0040] The second positive electrode connecting plate 41 is placed between the first positive electrode connecting plate 31 and the first negative electrode connecting plate 32 . The second negative electrode connecting plate 42 is placed at the end of the first negative electrode connecting plate 32 away from the second positive electrode connecting plate 41 . The connecting rod 21 is fixedly connected to the first positive electrode connecting plate 31 and the first negative electrode connecting plate 32 .

[0041] The actuator 2 controls the connecting rod 21 to electrically connect the first positive electrode connecting plate 31 with the second positive electrode connecting plate 41 and the first negative electrode connecting plate 32 with the second negative electrode connecting plate 42 according to the signal of the controller 1; or the actuator 2 controls the connecting rod 21 to electrically connect the first negative electrode connecting plate 32 with the second positive electrode connecting plate 41 according to the signal of the controller 1.

[0042] Connecting pieces are led out from both ends of the positive and negative electrodes of the two battery packs, so that the connecting rod 21 can drive the connecting piece to move, thereby controlling the two battery packs to be connected in series or in parallel.

[0043] The first positive electrode connecting sheet 31 and the first negative electrode connecting sheet 32 ​​are flexible conductive sheets, and the second positive electrode connecting sheet 41 and the second negative electrode connecting sheet 42 are rigid conductive sheets.

[0044] The connecting rod 21 drives the first positive electrode connecting plate 31 and the first negative electrode connecting plate 32 to move, and these two connecting plates are set to a flexible conductive plate structure for easy movement; and the second positive electrode connecting plate 41 and the second negative electrode connecting plate 42 are used as the connected ends. By setting them to a rigid conductive plate structure, the position is guaranteed not to be offset and the stability of the connection is ensured.

[0045] In this embodiment, a first conductive moving contact 311 is provided at the end of the first positive electrode connecting plate 31 close to the second positive electrode connecting plate 41, and a second conductive moving contact 321 is provided at the end of the first negative electrode connecting plate 32 close to the second positive electrode connecting plate 41 and close to the second negative electrode connecting plate 42.

[0046] By providing a conductive moving contact, electrical connection can be performed in advance, thereby preventing the connection piece from being deformed due to long-term use and causing unstable connection.

[0047] Furthermore, a first conductive static contact 411 is provided on the second positive electrode connecting piece 41 below the end of the first positive electrode connecting piece 31, a second conductive static contact 412 is provided on the second positive electrode connecting piece 41 above the end of the first negative electrode connecting piece 32, and a third conductive static contact 421 is provided on the second negative electrode connecting piece 42 below the end of the first negative electrode connecting piece 32.

[0048] Adding conductive static contacts ensures that the connecting piece has a better connection end and facilitates connection.

[0049] In this embodiment, the second positive electrode connecting plate 41 includes a first conductive plate 51 arranged on a side close to the first positive electrode connecting plate 31, a second conductive plate 52 arranged on a side close to the second negative electrode connecting plate 42, and a third conductive plate 53 for electrically connecting the first conductive plate 51 and the second conductive plate 52.

[0050] The first conductive sheet 51 and the third conductive sheet 53 are vertically fixedly connected, the third conductive sheet 53 and the second conductive sheet 52 are vertically fixedly connected, the first conductive sheet 51 is electrically connected to the positive pole of the second battery group 4, the first conductive static contact 411 is arranged on the first conductive sheet 51, and the second conductive static contact 412 is arranged on the second conductive sheet 52.

[0051] The second positive electrode connecting sheet 41 is split into three conductive sheets for easy installation, ensuring a sufficient safety distance between the positive and negative electrodes and facilitating the installation of two battery packs.

[0052] In this embodiment, the controller 1 is a chip or circuit capable of realizing data transmission and reception in the prior art. The input end of the controller 1 is electrically connected to the electric vehicle or electrical equipment to receive a series control instruction or a parallel control instruction.

[0053] The output end of the actuator 2 is connected to the connecting rod 21, which is made of insulating rigid material and only provides the function of simultaneously driving the first positive electrode connecting piece 31 and the first negative electrode connecting piece 32 to move. Specifically, the end of the connecting rod 21 connected to the first positive electrode connecting piece 31 is a node 1, and the end of the connecting rod 21 connected to the second negative electrode connecting piece 32 is a node 2. Nodes 1 and 2 can be fixed by welding. At the same time, the connecting rod 21 between nodes 1 and 2 is a wooden insulating structure.

[0054] The actuator 2 can be a telescopic motor, that is, the output end of the telescopic motor is fixedly connected to the connecting rod 21, so as to drive the connecting rod 21 to achieve up and down telescopic movement, and then drive the movement of the first positive connecting plate 31 and the first negative connecting plate 32, to achieve connection with the second positive connecting plate 41 and the second negative connecting plate 42, so as to achieve the purpose of connecting two battery packs in series or in parallel.

[0055] The actuator 2 controls the movement of the connecting rod 21 according to the instruction of the controller 1. This process can be completed without a program and can be realized in the prior art.

[0056] Specific:

[0057] See also Figure 1As shown, in the normal state, the first positive electrode connecting piece 31 and the first negative electrode connecting piece 32 connected by the connecting rod 21 are in a suspended state, that is, they are not involved in any connection, so that the two battery packs are independent. Of course, it can also be set to be in a parallel state or a series state by default, and then after receiving an instruction, the state is switched.

[0058] See also Figure 2 As shown, after receiving the series connection instruction from the electrical equipment, the controller 1 sends it to the actuator 2. The actuator 2 controls the connecting rod 21 to move upward, and the first negative electrode connecting piece 32 is crimped with the second positive electrode connecting piece 41 to achieve electrical connection, that is, the second conductive moving contact 321 is crimped with the second conductive static contact 412 to achieve electrical connection, so that the negative electrode of the first battery group 3 is electrically connected with the positive electrode of the second battery group, and the first battery group 3 and the second battery group 4 form a series connection state. The voltage between the output + of the positive electrode of the first battery group 3 and the output - of the negative electrode of the second battery group 4 is the series connection voltage. At this time, the battery pack is in a series connection high voltage state and can accept high voltage fast charging, or can drive a high voltage load.

[0059] If the overall structure of the electric vehicle with the switch device installed adopts the 400V voltage standard, that is to say, the electric vehicle adopts the 400V voltage output of the battery pack during normal driving, at this time, the switch device is in the parallel state by default, that is, the battery pack module (the first battery pack 3 and the second battery pack 4) is in the parallel state. If the above-mentioned vehicle model needs to be charged on a 400V charging device, the vehicle battery pack can be directly connected to the charging device without changing the state of the switch device, and a higher charging rate can be obtained. If the above-mentioned vehicle model needs to be charged on an 800V charging device, the vehicle system can change the state of the switch device through a control signal, switch the parallel state of the battery pack module to the series state, and the battery pack outputs 800V high voltage. At this time, it is directly connected to the 800V high voltage charging device to obtain a higher charging rate of 800V. After the 800V charging is completed, the external charging device is disconnected, the switch is restored to the parallel state, and the vehicle can be driven normally.

[0060] See also Figure 3As shown, after receiving the parallel instruction from the electrical equipment, the controller 1 sends it to the actuator 2, and the actuator 2 controls the connecting rod 21 to move downward, and the first positive connecting piece 31 is crimped with the second positive connecting piece 41 to achieve electrical connection, and the first negative connecting piece 32 is crimped with the second negative connecting piece 42 to achieve electrical connection, that is, the first conductive moving contact 311 is crimped with the first conductive static contact 411 to achieve electrical connection, and the second conductive moving contact 321 is crimped with the third conductive moving contact 421 to achieve electrical connection, so that the first battery pack 3 and the second battery pack 4 are in a parallel state, and the voltage between the output + of the positive electrode of the first battery pack 3 and the output - of the negative electrode of the second battery pack 4 is the parallel voltage. At this time, the battery pack is in a parallel low voltage state, which can accept low voltage compatible charging, or can drive a low voltage load.

[0061] If the overall structure of the electric vehicle with the switch device installed adopts the 800V voltage standard, that is to say, the electric vehicle adopts the 800V voltage output of the battery pack during normal driving, at this time, the switch device is in the series state by default, that is, the battery pack module (the first battery pack 3 and the second battery pack 4) is in the series state. If the above-mentioned vehicle model needs to be charged on an 800V charging device, the vehicle battery pack can be directly connected to the charging device without changing the state of the switch, and a higher charging rate can be obtained. If the above-mentioned vehicle model needs to be charged on a 400V charging device, the vehicle system can change the state of the switch device through a control signal, switch the series state of the battery pack module to a parallel state, and the battery pack outputs a 400V low voltage. At this time, it is directly connected to the 400V low-voltage charging device to obtain a 400V charging rate. After the 400V charging is completed, the external charging device is disconnected, the switch device is restored to the series state, and the vehicle can be driven normally.

[0062] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "in the present embodiment", "specific example", or "some examples" etc. means that the specific features, mechanisms, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, mechanisms, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0063] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A switch device for switching the series and parallel states of a battery pack module, characterized in that: It comprises a controller (1), an actuator (2), a first battery pack (3) and a second battery pack (4); The input end of the controller (1) is electrically connected to the electrical equipment, the output end of the controller (1) is electrically connected to the input end of the actuator (2), and the output end of the actuator (2) is fixedly connected to a connecting rod (21); the actuator (2) controls the connecting rod (21) to drive the first battery group (3) and the second battery group (4) to be connected in parallel or in series according to a signal from the controller (1); the first battery group (3) and the second battery group (4) are electrically connected to the electric vehicle load or charging equipment after being connected in parallel or in series.

2. The switch device for switching the series-parallel state of the battery pack module according to claim 1, characterized in that: The positive electrode of the first battery group (3) is electrically connected to the first positive electrode connecting sheet (31), the negative electrode of the first battery group (3) is electrically connected to the first negative electrode connecting sheet (32), the positive electrode of the second battery group (4) is electrically connected to the second positive electrode connecting sheet (41), and the negative electrode of the second battery group (4) is electrically connected to the second negative electrode connecting sheet (42); The second positive electrode connecting sheet (41) is disposed between the first positive electrode connecting sheet (31) and the first negative electrode connecting sheet (32); the second negative electrode connecting sheet (42) is disposed at an end of the first negative electrode connecting sheet (32) away from the second positive electrode connecting sheet (41); and the connecting rod (21) is fixedly connected to the first positive electrode connecting sheet (31) and the first negative electrode connecting sheet (32); The actuator (2) controls the connecting rod (21) to drive the first positive electrode connecting plate (31) to be electrically connected to the second positive electrode connecting plate (41), and to drive the first negative electrode connecting plate (32) to be electrically connected to the second negative electrode connecting plate (42) according to a signal from the controller (1); or the actuator (2) controls the connecting rod (21) to drive the first negative electrode connecting plate (32) to be electrically connected to the second positive electrode connecting plate (41) according to a signal from the controller (1).

3. The switch device for switching the series-parallel state of the battery pack module according to claim 2, characterized in that: The first positive electrode connecting sheet (31) and the first negative electrode connecting sheet (32) are flexible conductive sheets, and the second positive electrode connecting sheet (41) and the second negative electrode connecting sheet (42) are rigid conductive sheets.

4. The switch device for switching the series-parallel state of the battery pack module according to claim 2, characterized in that: A first conductive movable contact (311) is provided at the end of the first positive electrode connecting sheet (31) on a side close to the second positive electrode connecting sheet (41), and a second conductive movable contact (321) is provided at the end of the first negative electrode connecting sheet (32) on a side close to the second positive electrode connecting sheet (41) and a side close to the second negative electrode connecting sheet (42).

5. The switch device for switching the series-parallel state of a battery pack module according to claim 2 or 4, characterized in that: The second positive electrode connecting piece (41) is provided with a first conductive static contact (411) below the end of the first positive electrode connecting piece (31), the second positive electrode connecting piece (41) is provided with a second conductive static contact (412) above the end of the first negative electrode connecting piece (32), and the second negative electrode connecting piece (42) is provided with a third conductive static contact (421) below the end of the first negative electrode connecting piece (32).

6. The switch device for switching the series-parallel state of the battery pack module according to claim 5, characterized in that: The second positive electrode connecting sheet (41) comprises a first conductive sheet (51) arranged on a side close to the first positive electrode connecting sheet (31), a second conductive sheet (52) arranged on a side close to the second negative electrode connecting sheet (42), and a third conductive sheet (53) for electrically connecting the first conductive sheet (51) and the second conductive sheet (52); The first conductive sheet (51) and the third conductive sheet (53) are vertically fixedly connected, the third conductive sheet (53) and the second conductive sheet (52) are vertically fixedly connected, the first conductive sheet (51) is electrically connected to the positive electrode of the second battery pack (4), the first conductive static contact (411) is arranged on the first conductive sheet (51), and the second conductive static contact (412) is arranged on the second conductive sheet (52).

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