A battery cell module series structure and control method thereof

Abstract

The present invention belongs to the technical field of battery cell module series connection, and specifically discloses a battery cell module series connection structure and a control method thereof, wherein the series connection structure includes a control module and a plurality of battery cell modules, the battery cell module includes a battery cell, an analog front end unit, a first switch and a second switch, and the control module is communicatively connected with the analog front end unit of the battery cell module, and is control-connected with the first switch, the second switch and the third switch. The present invention controls the switch of the battery cell module through the control module, and can flexibly realize the series connection and isolation of the battery cell module in the series connection structure. When the battery cell module works abnormally, the isolation ensures the system reliability of the battery series connection structure; and the independent charging of each battery cell module can be realized by controlling the switch, ensuring that each battery cell module can obtain appropriate charging and discharging when battery cell modules with different SOCs are mixed, thereby increasing the service life of the system.

Description

Technical Field

[0001] The present invention belongs to the technical field of series connection of battery cell modules, and in particular relates to a series connection structure of battery cell modules and a control method thereof. Background Art

[0002] With the rapid development of the photovoltaic energy storage industry, more and more household energy storage and small-scale industrial and commercial energy storage are using battery pack series connection solutions. The voltage of the battery part of the energy storage system changes from low voltage to higher voltage. At the same time, the system solution changes from a low-voltage parallel connection of multiple battery modules to a series connection of multiple battery modules.

[0003] In the prior art, most high-voltage battery systems consist of two parts: a main control box and several battery modules. The main control box has main power circuit control, communication interaction, and BMS system. The battery modules are composed of BMU, AFE, and PACK. There are several problems in this solution system: This high-voltage series solution has the advantages of low cost, low current, and easy installation in high-power systems. However, there are also some problems: the abnormality of a single battery module in the system will cause the entire high-voltage system to fail to work, making the overall reliability of the system poor; at the same time, when battery packs of different SOCs and new and old degrees are mixed in the series system, the battery module with low SOC cannot be fully charged, and the battery module with high SOC cannot be fully discharged, causing the SOC display of the battery system to be confused and mutated, and even shortening the system life; the system discharge depth DOD is inconsistent, resulting in the system charging and discharging capacity cannot be maximized and the overall life of the system is affected. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of the prior art that the system stability of the multi-cell module series solution is poor and the mixed use of batteries with different SOCs is limited, thereby providing a cell module series structure and a control method thereof.

[0005] A battery cell module series structure comprises a control module and a plurality of battery cell modules, at least one of the battery cell modules is connected in series in a series branch; the battery cell module comprises a battery cell, an analog front end unit, a first switch and a second switch; the second switch is a single-pole double-throw switch; the battery cell is connected in parallel to the analog front end unit; the fixed end of the second switch is connected to the negative output end of the analog front end unit; when the movable end of the second switch is connected to the first output end, the corresponding battery cell module is connected in series in the series branch; when the first switch is closed, the corresponding battery cell module is short-circuited in the series branch; when the movable end of the second switch is connected to the second output end, the negative output end of each battery cell module is connected to the first end of the third switch, and the second end of the third switch is connected to the negative output end of the series structure; the control module is communicatively connected to the analog front end unit of each battery cell module, and is controllably connected to the first switch, the second switch and the third switch.

[0006] Furthermore, the battery cell module also includes a first diode and an inductor, the inductor is connected between the negative output end of the analog front-end unit and the second switch, and the cathode and anode of the first diode are respectively connected to the positive output end of the analog front-end unit and the fixed end of the second switch.

[0007] Furthermore, the third switch is a switch tube and further includes a second diode, and the second diode is connected in reverse parallel to the third switch.

[0008] Furthermore, one third switch is provided, and the second output end of the second switch of each battery cell module is connected to the negative output end of the series structure through the third switch.

[0009] Furthermore, a plurality of the third switches are provided, which are paired with the battery modules in pairs, and the second output end of the second switch of each battery module is connected to the negative output end of the series structure through one of the third switches.

[0010] Furthermore, the first switch and the second switch are relays.

[0011] A control method for a battery cell module series structure, the battery cell module series structure as described above, comprising:

[0012] When the battery cell module is connected in series in the series branch, the first switch is controlled to be disconnected, and the second switch is controlled to connect the negative output terminal of the analog front end unit with the series branch;

[0013] When isolating the battery cell module from the series branch, controlling the first switch to close, and controlling the second switch to connect the negative output terminal of the analog front end unit and the first terminal of the third switch;

[0014] An end close to the negative output end of the series structure is defined as the end; when the battery cell module is charged, if the battery cell module is not the last battery cell module, the first switch is controlled to close, and the second switch is controlled to connect the negative output end of the analog front-end unit and the first end of the third switch.

[0015] Furthermore, the control method is also included:

[0016] The third switches and the battery modules are arranged in pairs and are respectively connected to the negative output end of the series structure;

[0017] When the battery cell module at the end is charged, the first switch of the battery cell module at the end is controlled to be disconnected, and the second switch is connected to the negative output end of the analog front-end unit and the first end of the third switch; at the same time, the first switch of the previous battery cell module is controlled to be closed, the second switch is connected to the negative output end of the analog front-end unit and the first end of the third switch, and the corresponding third switch of the previous battery cell module is closed.

[0018] Furthermore, the control method is also included:

[0019] The third switch is provided with one and connected to the negative output end of the series structure;

[0020] When the battery cell module at the end is charged, the first switch of the battery cell module at the end is controlled to be disconnected, and the second switch is connected to the negative output end of the analog front-end unit and the series branch; at the same time, the first switch of the previous battery cell module is controlled to be closed, and the second switch is connected to the negative output end of the analog front-end unit and the first end of the third switch.

[0021] Furthermore, the control method is also included:

[0022] When the battery cell module at the end is isolated from the series branch, the first switch of the battery cell module at the end is controlled to be closed; and the first switch of the previous battery cell module is controlled to be disconnected, and the second switch connects the negative output end of the analog front-end unit and the first end of the third switch, corresponding to the closure of the third switch.

[0023] Beneficial effects: The present invention discloses a battery cell module series structure and a control method thereof, wherein the series structure includes a control module and a plurality of battery cell modules, wherein the battery cell module includes a battery cell, an analog front end unit, a first switch and a second switch, and the control module is communicatively connected to the analog front end unit of the battery cell module, and is control-connected to the first switch, the second switch and the third switch. The present invention controls the switches of the battery cell modules through the control module, and can flexibly realize the series connection and isolation of the battery cell modules in the series structure. When the battery cell modules work abnormally, the isolation ensures the system reliability of the battery series structure; and the independent charging of each battery cell module can be realized by controlling the switch, ensuring that each battery cell module can obtain appropriate charging and discharging when battery cell modules of different SOCs are mixed, thereby increasing the service life of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is a schematic block diagram of the battery module structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the connection of the battery module of the present invention;

[0027] Figure 3 It is a circuit schematic diagram of the battery module of the present invention;

[0028] Figure 4 A circuit schematic diagram of a battery module connection of the present invention;

[0029] Figure 5 This is a circuit schematic diagram of another battery module connection of the present invention.

[0030] Description of reference numerals:

[0031] K1, first switch; K2, second switch; Q1, third switch; L1, inductor; D1, first diode; V, battery cell; AFE, analog front end unit; D2, second diode. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0033] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0034] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0035] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0036] Embodiment 1:

[0037] Reference Figure 1 , Figure 2 and Figure 3As shown, this embodiment provides a battery module series structure, including a control module and multiple battery modules, at least one of the battery module is connected in series in a series branch; the battery module includes a battery V, an analog front end unit AFE, a first switch K1 and a second switch k2; the second switch k2 is a single-pole double-throw switch; the battery cell is connected in parallel to the analog front end unit AFE; the fixed end of the second switch k2 is connected to the negative output end of the analog front end unit AFE; when the moving end of the second switch k2 is connected to the first output end, the corresponding battery module is connected in series on the series branch; when the first switch K1 is closed, the corresponding battery module is short-circuited on the series branch; when the moving end of the second switch k2 is connected to the second output end, the negative output end of each battery module is connected to the first end of the third switch Q1, and the second end of the third switch Q1 is connected to the negative output end of the series structure; the control module is communicated with the analog front end unit AFE of each battery module, and is controlled and connected with the first switch K1, the second switch k2 and the third switch Q1.

[0038] Specifically, the battery core module also includes a first diode D1 and an inductor L1, the inductor L1 is connected between the negative output end of the analog front-end unit AFE and the second switch k2, and the cathode and anode of the first diode D1 are respectively connected to the positive output end of the analog front-end unit AFE and the fixed end of the second switch k2.

[0039] As a preference of this embodiment, the third switch Q1 is a switch tube and further includes a second diode D2 , and the second diode D2 is connected in reverse parallel to the third switch Q1 .

[0040] Reference Figure 3 As shown, it includes a battery cell, an analog front-end unit AFE, a first switch K1, a second switch k2, a third switch Q1, an inductor L1, a first diode D1, and a second diode D2; the battery cell is connected in parallel with the analog front-end unit AFE; the first end of the inductor L1 is connected to the negative output end of the analog front-end unit AFE, and the second end is connected to the fixed end of the second switch k2; the cathode of the first diode D1 is connected to the second end of the inductor L1, and the anode is connected to the positive output end of the analog front-end unit AFE; the first end of the first switch K1 is connected to the positive output end of the analog front-end unit AFE as the positive output end of the battery cell module, and the negative output end is connected to the first output end of the second switch k2 as the negative output end of the battery cell module; the second output end of the third switch Q1 is connected to the negative output end of the series structure; the second diode D2 is reversely connected to the third switch Q1 in parallel; the control module is respectively connected to and controls the control ends of the first switch K1, the second switch k2, and the third switch Q1, and is communicatively connected with the analog front-end unit AFE.

[0041] Reference Figure 4 As shown, in some implementations of this embodiment, the third switch Q1 is provided, and the second output end of the second switch k2 of each of the battery module is connected to the negative output end of the series structure through the third switch Q1. In this implementation, a total of N battery modules are provided, K11~K1N, K21~k2N, Q1~QN are respectively the first switch K1, the second switch k2, and the third switch Q1 of the 1st to Nth battery modules, and V+ and V- are respectively the positive output end and the negative output end of the series structure.

[0042] Reference Figure 5 As shown, in some other implementations of this embodiment, the third switch Q1 is provided in plurality, and is paired with the battery modules in pairs, and the second output end of the second switch k2 of each battery module is connected to the negative output end of the series structure through a third switch Q1. In this implementation, a total of N battery modules are provided, K11~K1N, K21~k2N, Q1~QN are respectively the first switch K1, the second switch k2, and the third switch Q1 of the 1st to Nth battery modules, and V+ and V- are respectively the positive output end and the negative output end of the series structure.

[0043] As a preference of this embodiment, the first switch K1 and the second switch k2 are relays, and the third switch Q1 is a field effect transistor.

[0044] In this embodiment, the control module is a battery management system (BMS). Specifically, the control module can be one of a single chip microcomputer, an MCU, a CPU, and an FPGA.

[0045] Embodiment 2:

[0046] This embodiment provides a control method for a series structure of battery cell modules, wherein the series structure of battery cell modules is as described in the first embodiment, including:

[0047] When the battery module is connected in series in the series branch, the first switch K1 is controlled to be disconnected, and the second switch k2 is controlled to connect the negative output terminal of the analog front end unit AFE and the series branch;

[0048] When isolating the battery module from the series branch, controlling the first switch K1 to close, and controlling the second switch k2 to connect the negative output terminal of the analog front end unit AFE and the first terminal of the third switch Q1;

[0049] An end close to the negative output end of the series structure is defined as the end; when the battery module is charged, if the battery module is not the last battery module, the first switch K1 is controlled to be closed, and the second switch k2 is controlled to connect the negative output end of the analog front end unit AFE and the first end of the third switch Q1.

[0050] In some implementations of this embodiment, when the battery cell module at the end is isolated from the series branch, the first switch K1 of the battery cell module at the end is controlled to be closed; and the first switch K1 of the previous battery cell module is controlled to be disconnected, and the second switch k2 connects the negative output end of the analog front-end unit AFE and the first end of the third switch Q1, corresponding to the closure of the third switch Q1.

[0051] In some implementations of the present embodiment, the third switch Q1 and the battery cell modules are arranged in pairs and are respectively connected to the negative output end of the series structure; when the battery cell module at the end is charged, the first switch K1 of the battery cell module at the end is controlled to be disconnected, and the second switch k2 is connected to the negative output end of the analog front-end unit AFE and the first end of the third switch Q1; at the same time, the first switch K1 of the previous battery cell module is controlled to be closed, the second switch k2 is connected to the negative output end of the analog front-end unit AFE and the first end of the third switch Q1, and the corresponding third switch Q1 of the previous battery cell module is closed.

[0052] In some other implementations of this embodiment, the third switch Q1 is set and connected to the negative output end of the series structure; when the battery cell module at the end is charged, the first switch K1 of the battery cell module at the end is controlled to be disconnected, and the second switch k2 is connected to the negative output end of the analog front-end unit AFE and the series branch; at the same time, the first switch K1 of the previous battery cell module is controlled to be closed, and the second switch k2 is connected to the negative output end of the analog front-end unit AFE and the first end of the third switch Q1.

[0053] In this embodiment, when the control module detects that the SOC of the battery cell is low through the analog front-end unit AFE, in order to charge the corresponding battery cell module, the first switch K1, the second switch k2, and the third switch Q1 are controlled to connect the current battery cell module in parallel to the output end of the series structure, and the first diode D1, the inductor L1, and the third switch Q1 in the battery cell module form a power loop, so that the series structure charges the current battery cell module through the DC / DC circuit. When the control module detects that the SOC of the battery cell is balanced with the battery cell module in the series structure through the analog front-end unit AFE, the charging is stopped, and the battery cell module is controlled to be connected in series back to the series branch.

[0054] In this embodiment, when the control module detects that the SOC of the battery cell is too high through the analog front-end unit AFE, in order to correspond to the balance of the battery cell module, the first switch K1, the second switch k2, and the third switch Q1 are controlled to isolate the current battery cell module from the series structure. When the control module detects that the SOC of the battery cell is balanced with the battery cell modules in the series structure through the analog front-end unit AFE, the battery cell module is isolated and controlled to be connected in series back to the series branch.

[0055] As a further improvement of this embodiment, when the control module detects an abnormality in the battery cell through the analog front end unit AFE, the first switch K1, the second switch k2 and the third switch Q1 are controlled to isolate the current battery cell module from the series structure.

[0056] In this embodiment, when a single battery cell module in the series structure is connected in series back to the series branch, the control module controls the first switch K1 to be disconnected, the second switch k2 connects the negative output end of the analog front-end unit AFE and the series branch, and the third switch Q1 is disconnected. The entire power loop passes through the inductor L1 in the power circuit. The inductor L1 is an energy storage device, and the current cannot change suddenly. Therefore, multiple inductors L1 in the series structure are connected in series, which can effectively suppress surge current.

[0057] The present invention provides a battery cell module series structure and a control method thereof, wherein the series structure includes a control module and a plurality of battery cell modules, wherein the battery cell module includes a battery cell, an analog front end unit AFE, a first switch K1 and a second switch k2, and the control module is connected to the analog front end unit AFE of the battery cell module in communication, and is connected to the first switch K1, the second switch k2 and the third switch Q1 in a controlled manner. The present invention controls the switches of the battery cell modules through the control module, and can flexibly realize the series connection and isolation of the battery cell modules in the series structure, and when the battery cell modules work abnormally, the isolation ensures the system reliability of the battery series structure; and the independent charging of each battery cell module can be realized by controlling the switch, ensuring that each battery cell module can obtain appropriate charging and discharging when battery cell modules with different SOCs are mixed, thereby increasing the service life of the system.

[0058] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0059] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed 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 battery cell module series structure, characterized in that: It comprises a control module and a plurality of battery cell modules, at least one of which is connected in series in a series branch; the battery cell module comprises a battery cell, an analog front end unit, a first switch and a second switch; the second switch is a single-pole double-throw switch; the battery cell is connected in parallel to the analog front end unit; the fixed end of the second switch is connected to the negative output end of the analog front end unit; when the movable end of the second switch is connected to the first output end, the corresponding battery cell module is connected in series in the series branch; when the first switch is closed, the corresponding battery cell module is short-circuited in the series branch; when the movable end of the second switch is connected to the second output end, the negative output end of each battery cell module is connected to the first end of the third switch, and the second end of the third switch is connected to the negative output end of the series structure; the control module is connected to the analog front end unit of each battery cell module in communication, and is control-connected to the first switch, the second switch and the third switch; The control module is used to control the first switch, the second switch and the third switch, so that the corresponding battery cell modules are connected in series in the series branch, isolate the series branch or charge; The control module is used to control the first switch to be disconnected, and control the second switch to connect the negative output terminal of the analog front end unit with the series branch, so that the corresponding battery cell module is connected in series in the series branch; The control module is used to control the first switch to be closed, and control the second switch to connect the negative output terminal of the analog front end unit and the first terminal of the third switch, so that the corresponding battery cell module is isolated from the series branch; The control module is used to control the first switch to close if the battery cell module is not the end battery cell module, and control the second switch to connect the negative output end of the analog front-end unit and the first end of the third switch, so that the corresponding battery cell module is charged, and the end close to the negative output end of the series structure is the end.

2. The battery cell module series structure according to claim 1, characterized in that: The battery cell module also includes a first diode and an inductor, wherein the inductor is connected between the negative output terminal of the analog front-end unit and the second switch, and the cathode and anode of the first diode are respectively connected to the positive output terminal of the analog front-end unit and the fixed end of the second switch.

3. The battery cell module series structure according to claim 2, characterized in that: The third switch is a switch tube and further includes a second diode, and the second diode is connected in reverse parallel to the third switch.

4. The battery cell module series structure according to claim 3, characterized in that: One third switch is provided, and the second output end of the second switch of each battery cell module is connected to the negative output end of the series structure through the third switch.

5. The battery cell module series structure according to claim 3, characterized in that: There are multiple third switches, which are paired with the battery modules in pairs. The second output end of the second switch of each battery module is connected to the negative output end of the series structure through one third switch.

6. The battery cell module series structure according to claim 1, characterized in that: The first switch and the second switch are relays.

7. A control method for a series structure of battery modules, characterized in that: The battery module series structure is as described in any one of claims 1 to 6, comprising: When the battery cell module is connected in series in the series branch, the first switch is controlled to be disconnected, and the second switch is controlled to connect the negative output terminal of the analog front end unit with the series branch; When isolating the battery cell module from the series branch, controlling the first switch to close, and controlling the second switch to connect the negative output terminal of the analog front end unit and the first terminal of the third switch; An end close to the negative output end of the series structure is defined as the end; when the battery cell module is charged, if the battery cell module is not the last battery cell module, the first switch is controlled to close, and the second switch is controlled to connect the negative output end of the analog front-end unit and the first end of the third switch.

8. The control method of a battery cell module series structure according to claim 7, characterized in that: Also includes control methods: The third switches and the battery modules are arranged in pairs and are respectively connected to the negative output ends of the series structure; When the battery cell module at the end is charged, the first switch of the battery cell module at the end is controlled to be disconnected, and the second switch is connected to the negative output end of the analog front-end unit and the first end of the third switch; at the same time, the first switch of the previous battery cell module is controlled to be closed, the second switch is connected to the negative output end of the analog front-end unit and the first end of the third switch, and the corresponding third switch of the previous battery cell module is closed.

9. The control method of a battery cell module series structure according to claim 7, characterized in that: Also includes control methods: The third switch is provided with one and connected to the negative output end of the series structure; When the battery cell module at the end is charged, the first switch of the battery cell module at the end is controlled to be disconnected, and the second switch is connected to the negative output end of the analog front-end unit and the series branch; at the same time, the first switch of the previous battery cell module is controlled to be closed, and the second switch is connected to the negative output end of the analog front-end unit and the first end of the third switch.

10. The control method of a battery cell module series structure according to claim 7, characterized in that: Also includes control methods: When the battery cell module at the end is isolated from the series branch, controlling the first switch of the battery cell module at the end to be closed; The first switch of the previous battery module is controlled to be disconnected, and the second switch connects the negative output end of the analog front-end unit and the first end of the third switch, corresponding to the closing of the third switch.

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