Battery

Abstract

The embodiment of the invention provides a battery matched with electric equipment for use, and the battery comprises a battery main body which is provided with a first tab; the circuit breaker comprises a first contact piece, a second contact piece and a thermal strain element, the first contact piece is connected between the first tab and the thermal strain element, and the second contact piece comprises a first end connected with the electric equipment and a second end in separable contact with a main body of the first contact piece. According to the battery provided by the invention, at least when the battery cell of the battery is heated, the circuit breaker can cut off or reduce the current in time, so that the battery cell is protected.

Description

[0001] The present invention is a divisional application with application number 201710642796.4, application date July 31, 2017, and invention name “Battery”. Technical Field

[0002] Embodiments of the present application relate to the field of batteries, and more particularly, to a battery. Background Art

[0003] In the current safety structure for batteries, it is common to connect an overheat protection device in series with the outside of the battery, such as a circuit breaker, to cut off or reduce the current when the battery cell temperature rises abnormally, thereby protecting the battery cell. However, the current circuit breaker usually has a delay in the operating temperature, and it is often the case that the battery temperature has risen abnormally but the circuit breaker still does not operate, thus failing to protect the battery cell. Summary of the invention

[0004] In view of the problems existing in the related art, the purpose of the present application is to provide a safe battery, so as to at least achieve the ability to cut off or reduce the current in time when the battery cell generates heat, thereby protecting the battery cell.

[0005] To achieve the above-mentioned purpose, the present application provides a battery for use with an electrical device, the battery comprising: a battery body, the battery body being provided with a first pole ear; and a circuit breaker, the circuit breaker comprising a first contact piece, a second contact piece and a thermal strain element, wherein the first contact piece is connected between the first pole ear and the thermal strain element, and the second contact piece comprises a first end connected to the electrical device and a second end which is detachably contacted with the body of the first contact piece.

[0006] According to an embodiment of the present application, the thermal strain element includes a thermal strain spring.

[0007] According to an embodiment of the present application, the thermal strain spring is an insulating member.

[0008] According to one embodiment of the present application, the thermal strain spring is a conductive member, the thermal strain element also includes a heat-conducting element connected to the first contact member, the heat-conducting element is thermally coupled to the thermal strain spring, the thermal strain spring is arranged between the heat-conducting element and the second contact member, the heat-conducting element is an insulating member or the heat-sensitive element.

[0009] According to an embodiment of the present application, the thermal strain element further includes: a heat conducting element connected to the first contact piece, the heat conducting element is thermally coupled to the thermal strain spring piece, and the thermal strain spring piece is arranged between the heat conducting element and the second contact piece.

[0010] According to an embodiment of the present application, the thermal strain spring includes a metal spring.

[0011] According to one embodiment of the present application, the thermal element includes a thermistor.

[0012] According to one embodiment of the present application, the battery further includes a transfer tab, wherein the transfer tab is connected between the first contact piece and the first tab.

[0013] According to an embodiment of the present application, the battery further includes a rolled-out tab, wherein the rolled-out tab is connected between the second contact piece and the electrical device.

[0014] According to one embodiment of the present application, the circuit breaker is located between the transfer tab and the output tab, wherein the circuit breaker, the transfer tab and the output tab are arranged in the same layer.

[0015] According to one embodiment of the present application, the transfer tab is located between the output tab and the circuit breaker, wherein the transfer tab and the circuit breaker are arranged in a first layer, and the output tab is arranged in a second layer.

[0016] According to one embodiment of the present application, the battery body is further provided with a second pole lug, wherein the second pole lug is connected to an electrical device.

[0017] According to an embodiment of the present application, the first electrode tab and the transfer electrode tab that are connected to each other are located between the second electrode tab and the transfer-out electrode tab.

[0018] According to one embodiment of the present application, the output electrode tab is located between the second electrode tab and the first electrode tab and the transfer electrode tab that are connected to each other.

[0019] According to one embodiment of the present application, a battery top sealing edge is also formed on the top of the battery body, and the circuit breaker is fixed on the battery top sealing edge, or the circuit breaker is fixed on the top of the battery body.

[0020] The beneficial technical effects of this application are:

[0021] In the battery of the present application, the first contact piece of the circuit breaker is respectively connected to the pole ear and the thermal strain element, so that the heat of the battery cell is directly transferred to the thermal strain element via the first contact piece. Therefore, the heat conduction path from the battery cell to the thermal strain element is shorter and the loss is less. The thermal strain element can sense the abnormal heating of the battery cell more promptly and cut off or reduce the current, thereby protecting the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] 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 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.

[0023] Figure 1 A schematic diagram showing the structure and heat conduction path of a circuit breaker in the prior art is shown;

[0024] Figure 2a A schematic diagram showing the structure and heat conduction path of a circuit breaker according to an embodiment of the present application is shown;

[0025] Figure 2b A schematic diagram showing the structure and heat conduction path of a circuit breaker according to another embodiment of the present application;

[0026] Figure 3 A schematic diagram showing a U-shaped layout of a transfer tab, a transfer tab and a circuit breaker according to an embodiment of the present application is shown;

[0027] Figure 4 A schematic diagram showing an F-type layout of a transfer tab, a transfer tab and a circuit breaker according to another embodiment of the present application is shown;

[0028] Figure 5 A schematic diagram of a battery according to an embodiment of the present application is shown;

[0029] Figure 6 A schematic diagram of a battery according to another embodiment of the present application is shown;

[0030] Figure 7 A schematic diagram showing a battery according to yet another embodiment of the present application; and

[0031] Figure 8 A comparison chart showing the operating temperatures of the thermal sensing elements of the embodiment and the comparative example is shown. DETAILED DESCRIPTION

[0032] The battery of the present application is now described with reference to the accompanying drawings. It should be understood that the corresponding exemplary embodiments in the following description and the accompanying drawings can be combined with each other to form other embodiments not described below; and some components thereof can be omitted in different embodiments. In other words, the following description does not limit the present application.

[0033] First refer to Figures 2a to 6 The embodiment of the present application discloses a battery 30 used in conjunction with an electrical device. The battery 30 generally includes a battery body 32 and a circuit breaker 10. Specifically, Figure 5 As shown, the battery body 32 is provided with a first tab 34, and as shown in FIG. Figure 2a and Figure 2bAs shown, the circuit breaker 10 includes a first contact 14, a second contact 16 and a thermal strain element 18. The two ends of the first contact 14 are respectively connected to the first pole ear 34 and the thermal strain element 18 to transfer heat from the first pole ear 34 to the thermal strain element 18 and to conduct electricity between the first pole ear 34 and the thermal strain element 18; the first end of the second contact 16 is connected to an external electrical device, and the second end is detachably in contact with the body of the first contact 14, wherein the body of the first contact 14 refers to the portion of the first contact 14 located between its two ends, specifically, the body of the first contact 14 is located between the first pole ear 34 and the thermal strain element 18.

[0034] It should be pointed out here that the "thermal strain element" mentioned above refers to an element that can change shape, size, or both shape and size when the temperature changes. The "separable contact" mentioned above means that the second contact member 16 can selectively contact the first contact member 14 or separate from the first contact member 14 based on different conditions. For example, when the temperature of the battery cell is within the normal operating temperature range and the thermal strain element 18 does not reach the strain temperature and maintains its original shape, the second contact member 16 maintains contact with the main body of the first contact member 14 to achieve the conductive function between the two; when the battery cell is overheated, for example, the battery cell temperature exceeds the normal operating temperature, the heat from the battery cell is transferred to the thermal strain element 18 via the first contact member 14 to deform the thermal strain element 18, and the deformed thermal strain element 18 bounces the second contact member 16 away from the main body of the first contact member 14.

[0035] For example, in the embodiments of the present application, Figure 2a As shown, the thermal strain element 18 may include a thermal strain spring 22, which is thermally coupled to the first contact 14 and can be elastically deformed when the temperature changes to selectively cause the second contact 16 to bounce away from the first contact 14. In one embodiment of the present application, the thermal strain spring 22 is an insulating member.

[0036] In addition, in the embodiments of the present application, Figure 2b As shown, the thermal strain element 18 further includes a heat-conducting element 20 connected to the first contact member 14, wherein the heat-conducting element 20 is thermally coupled to the thermal strain spring 22 to transfer heat from the first contact member 14 to the thermal strain spring 22, and the thermal strain spring 22 is disposed between the heat-conducting element 20 and the second contact member 16. In this embodiment, the thermal strain spring 22 receives heat from the first contact member 14 through the heat-conducting element 20. Compared with the above embodiment in which the thermal strain element 22 is directly in contact with the first contact member 14 to receive heat, the contact area between the thermal strain spring 22 and the heat-conducting element 20 is larger, and thus has a better heat conduction effect.

[0037] When the thermal strain spring piece 22 is an insulating member, there is no need to worry about a large current still existing in the circuit after the thermal strain spring piece 22 is deformed. The thermal conductive element 20 can be an insulating member or a conductive member.

[0038] When the thermal strain spring piece 22 is a conductive member, the heat conducting element 20 may be an insulating member. In this case, the circuit can be in an open circuit state after the thermal strain spring piece 22 is deformed, thereby ensuring the safety of the battery.

[0039] When the thermal strain spring 22 is a conductive member, the thermal conductive element 20 may be a thermistor. It should be noted here that the "thermistor" mentioned above refers to an element whose internal resistance increases when the temperature rises, so that the current in the circuit where the thermistor is located decreases; or it becomes an insulator when the temperature rises. When the internal resistance of the thermistor increases and it becomes an insulator, it is equivalent to causing the circuit to be broken, which can achieve the purpose of protecting the circuit. In addition, in order to achieve the effect of maintaining the deformation of the spring for a long time, the thermistor may also have the performance of generating heat when current passes through. For example, in the above-mentioned embodiment or other embodiments of the present application, the thermistor may include a thermistor, which may be a positive temperature coefficient thermistor according to one embodiment.

[0040] In addition, in the above-mentioned embodiment or other embodiments of the present application, the thermal strain spring 22 may include a metal spring or any spring made of other thermal strain materials known in the art. In addition, the thermal strain spring 22 may be a spring of a single-layer structure, or a spring of a double-layer or multi-layer structure, and the present application is not limited thereto. When the thermal strain spring 22 is a metal spring, an insulating layer may be disposed on the surface of the metal spring to ensure the insulation of the thermal strain spring 22.

[0041] Next, if Figure 5 As shown, in one embodiment of the present application, a battery top seal 38 is further formed on the top of the battery body 32, and the circuit breaker 10 is fixed on the battery top seal 38 by, for example, an adhesive. Alternatively, in one embodiment of the present application, as Figure 7 As shown, the circuit breaker 10 can be fixed on the top of the battery body 32. Figure 2a and Figure 2b An opening is provided on the bottom surface of the circuit breaker 10 , and the thermal strain element 18 is thermally coupled to the battery top seal 38 via the opening to receive heat from the battery top seal 38 .

[0042] In such Figure 2a and Figure 2bIn the embodiment of the present application shown, as shown by the arrows, there are two heat conduction paths from the battery cell to the thermal strain element 18 in the circuit breaker 10, as indicated by the arrows, namely the first heat conduction path: battery cell → first contact 14 → thermal strain element 18; and the second heat conduction path: battery cell → battery top seal 38 → thermal strain element 18. Here, the first heat conduction path and the second heat conduction path are only general heat transfer paths, and do not limit the specific heat transfer paths. For example, in the second heat conduction path, there can also be a glue layer between the battery top seal 38 and the thermal strain element 18. At this time, the specific heat transfer path in the second heat conduction path is battery cell → battery top seal 38 → glue layer → thermal strain element 18.

[0043] Similarly, in Figure 1 In the circuit breaker 10 of the prior art shown in FIG. 1 , the second contact 16 of the circuit breaker 10 is connected to the first pole ear 34, and the first contact 14 is connected to the external electrical device. Figure 1 In the circuit breaker 10 shown, as indicated by the arrows, the battery cell to the thermal strain element 18 also includes two heat conduction paths, namely the first heat conduction path: battery cell → second contact 16 → first contact 14 → thermal strain element 18; and the second heat conduction path: battery cell → battery top seal 38 → thermal strain element 18. Among them, in the first heat conduction path, the second contact 16 needs to cross the entire circuit breaker 10, and then contact the first contact 14 through a contact with a larger thermal resistance. Similarly, the first heat conduction path and the second heat conduction path here are only general heat transfer paths, and do not limit the specific heat transfer paths.

[0044] In comparison, Figure 1 Compared to the first heat conduction path of the prior art circuit breaker 10, Figure 2a and Figure 2b The first heat conduction path of the circuit breaker 10 of the present application is shorter and has less loss, so the thermal strain element 18 can sense the abnormal heating of the battery cell more timely and cut off or reduce the current, thereby protecting the battery cell.

[0045] Reference Figure 3 and Figure 4 According to one embodiment of the present application, the battery 30 also includes a transfer tab 24, wherein the transfer tab 24 is connected between the first contact member 14 and the first tab 34, that is, in this embodiment of the present application, the first contact member 14 is connected to the first tab 34 via the transfer tab 24; of course, in other embodiments of the present application, the first contact member 14 may also be directly welded to the first tab 34, and the present application is not limited thereto.

[0046] See also Figure 3 and Figure 4In another embodiment of the present application, in addition to the transfer tab 24, the battery 30 also includes a transfer tab 26, wherein the transfer tab 26 is connected between the second contact 16 and the electrical device, that is, in this embodiment of the present application, the second contact 16 is connected to the electrical device through the transfer tab 26.

[0047] Generally, considering that the circuit breaker 10 needs to be set close to the battery top seal 38, the transfer tab 24 and the transfer tab 26 are generally fixedly connected to the first contact 14 and the second contact 16 of the circuit breaker 10 in a U-shaped layout with a relatively simple structure. Figure 3 As shown, in one embodiment of the present application, the transfer tab 24 and the output tab 26 are respectively connected to both sides of the circuit breaker 10, so that the circuit breaker 10 is located between the transfer tab 24 and the output tab 26, and the circuit breaker 10, the transfer tab 24 and the output tab 26 are arranged in the same layer. In this structure, the circuit breaker 10, the transfer tab 24 and the output tab 26 roughly form Figure 3 U-shaped layout shown.

[0048] However, due to some special requirements on the cell structure, the F-type layout must be adopted in some cases, specifically, Figure 4 As shown, in the F-type layout, the transfer tab 24 and the output tab 26 are both located on the same side of the circuit breaker 10. At this time, the transfer tab 24 is located between the output tab 26 and the circuit breaker 10. In this structure, the transfer tab 24 and the circuit breaker 10 are arranged in the first layer, and the output tab 26 is arranged in the second side different from the first layer. The three generally form Figure 4 In the F-type layout, there is usually a layer of nickel sheet wrapped with adhesive tape between the circuit breaker 10 and the battery top seal 38, and the circuit breaker 10 and the battery top seal 38 are not in direct contact, so the second heat conduction path at the bottom of the circuit breaker 10 is blocked. Figure 1 still Figure 2a and Figure 2b The circuit breakers 10 shown can only function through the first heat conduction path. Therefore, when a circuit breaker with an F-type layout or other circuit breakers with blocked second heat conduction paths are used in a battery, Figure 2a and Figure 2b The heat conduction path of the circuit breaker 10 of the present application is shown as compared to Figure 1 The heat conduction path of the circuit breaker 10 of the prior art shown will improve the heat conduction effect more significantly. It can be seen that the embodiments of the present application improve the application scope and practicality of other similar layouts such as the F-type layout.

[0049] Next, refer to Figure 5 and Figure 6According to one embodiment of the present application, a second pole ear 36 is further provided on the top of the battery body 32, and the second pole ear 36 is connected to the electrical device. Figure 5 In the embodiment shown, the first pole tab 34 and the transfer pole tab 24 connected to each other are located between the second pole tab 36 and the transfer pole tab 26; Figure 6 In the illustrated embodiment, the output tab 26 is located between the second tab 36 and the first tab 34 and the transfer tab 24 that are connected to each other.

[0050] When the battery 30 of the present application is used, the circuit breaker 10 is bonded to the battery top seal 38 by an adhesive. Figure 2b Taking the circuit breaker 10 shown as an example, the adapter tab 24 is welded to the first tab 34, and the heat of the battery cell is transferred to the circuit breaker 10 via the first heat conduction path and the second heat conduction path. The heat in the circuit breaker 10 is transferred to the thermal strain spring 22 via the thermistor 20 (for example, thermistor). The heat of the thermal strain spring 22 gradually accumulates. When the thermal strain spring 22 reaches the designed operating temperature, it rebounds and deforms, and the second contact 16 is bounced off. The current begins to change the path from the first contact 14 to the thermistor 20. When a large current (for example, >0.3A) flows through the thermistor 20, its impedance instantly increases to the hundred ohms or thousand ohms level (the original impedance is about 10 ohms), which is equivalent to suddenly inserting a large resistor in series in the circuit, and the circuit is close to being disconnected, thereby blocking the reaction process that causes the temperature to rise (including reaction heat and Joule heat), and the battery cell temperature begins to drop, avoiding the battery cell combustion caused by thermal runaway.

[0051] A comparative test is now conducted on the battery of the present application and the battery of the prior art. A total of two groups of comparative tests are conducted. The first group of tests includes Example 1 and Comparative Example 1, both of which use the circuit breaker connection method of the present application and the circuit breaker connection method of the prior art, respectively, and perform 1C / 12V overcharge tests on the batteries in Example 1 and Comparative Example 1, respectively; the second group of tests includes Example 2 and Comparative Example 2, both of which use the circuit breaker connection method of the present application and the circuit breaker connection method of the prior art, respectively, and perform 1C / 12V overcharge tests on the batteries in Example 2 and Comparative Example 2, respectively. The 1C / 12V overcharge test refers to: charging the battery with a 1C constant current, and when the voltage reaches 12V, switching from the constant current mode to the constant voltage mode, and maintaining the constant voltage for 1h. If the battery does not smoke, burn, or explode during this overcharge test, it passes the overcharge, otherwise it fails. See Table 1 and the attached for the test results. Figure 8 The diagram shown in:

[0052] Table 1: Overcharge pass rate of examples and comparative examples

[0053] project Example 1 Comparative Example 1 Example 2 Comparative Example 2 1C / 12V overcharge 9 / 10 Passed 1 / 10 passed 6 / 10 Passed 0 / 10 Pass

[0054] By comparing the results of Example 1 with those of Comparative Example 1 and the results of Example 2 with those of Comparative Example 2, it can be seen that the overcharge pass rate of the battery of the present application has been significantly improved. Figure 8 According to the action temperature data shown, the action temperature of the thermal strain element of Example 1 and Example 2 is about 5°C earlier than that of Comparative Example 1 and Comparative Example 2. It can be seen that compared with the prior art, the thermal strain element 18 in the battery of the embodiment of the present application can more timely sense the abnormal heating of the battery cell and cut off or reduce the current, thereby protecting the battery cell.

[0055] The above description is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery, characterized in that: include: A battery body is provided with a first pole ear; and a circuit breaker includes a first contact piece, a second contact piece and a thermal strain element, wherein the first contact piece is connected between the first pole ear and the thermal strain element, and the second contact piece includes a first end connected to an electrical device and a second end detachably contacting with a main body of the first contact piece, The thermal strain element further comprises a heat conducting element connected to the first contact member, the heat conducting element is thermally coupled to the thermal strain spring sheet, and the thermal strain spring sheet is arranged between the heat conducting element and the second contact member. It also includes a transfer tab, which is L-shaped. A battery top seal is also formed on the top of the battery body, an opening is provided on the bottom surface of the circuit breaker, and the circuit breaker is thermally coupled to the battery top seal via the opening.

2. The battery according to claim 1, characterized in that The thermal strain element includes a thermal strain spring.

3. The battery according to claim 2, characterized in that The thermal strain spring piece is an insulating member.

4. The battery according to claim 2, characterized in that The thermal strain spring is a conductive member, the heat conducting element is an insulating member or the heat conducting element is a thermosensitive element.

5. The battery according to claim 2, characterized in that The thermal strain spring piece includes a metal spring piece.

6. The battery according to claim 4, characterized in that The thermal element includes a thermistor.

7. The battery according to claim 1, characterized in that The transfer tab is connected between the first contact piece and the first tab.

8. The battery according to claim 7, characterized in that It also includes a turned-out tab, wherein the turned-out tab is connected between the second contact piece and the electrical device.

9. The battery according to claim 8, characterized in that The circuit breaker is located between the transfer tab and the output tab, wherein the circuit breaker, the transfer tab and the output tab are arranged in the same layer.

10. The battery according to claim 8, characterized in that The transfer tab is located between the output tab and the circuit breaker, wherein the transfer tab and the circuit breaker are arranged in a first layer, and the output tab is arranged in a second layer.

11. The battery according to claim 8, characterized in that The battery body is also provided with a second pole lug, wherein the second pole lug is connected to the electrical device.

12. The battery according to claim 11, characterized in that The first pole tab and the transfer pole tab that are connected to each other are located between the second pole tab and the transfer pole tab.

13. The battery according to claim 11, characterized in that The output electrode tab is located between the second electrode tab and the first electrode tab and the transfer electrode tab that are connected to each other.

14. The battery according to claim 1, characterized in that The circuit breaker is fixed on the top of the battery body.

Images